diff --git a/BUILD b/BUILD
index 69fb88c..3e17a1d 100644
--- a/BUILD
+++ b/BUILD
@@ -6,14 +6,10 @@
     srcs = glob(["src/main/java/**/*.java"]),
     manifest_entries = [
         "Gerrit-PluginName: uploadvalidator",
-        "Gerrit-ApiVersion: 2.14",
+        "Gerrit-ApiVersion: 2.15-SNAPSHOT",
         "Gerrit-Module: com.googlesource.gerrit.plugins.uploadvalidator.Module",
     ],
     resources = glob(["src/main/resources/**/*"]),
-    deps = [
-        "@commons_io//jar",
-        "@tika_core//jar",
-    ],
 )
 
 TEST_SRCS = "src/test/java/**/*Test.java"
diff --git a/WORKSPACE b/WORKSPACE
index f6203aec..09a5ba2 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "714a32382ebd02919007d3514513af4395768d80",
+    commit = "b54eaed487d37188120da6933b97c571519954ca",
     #local_path = "/home/<user>/projects/bazlets",
 )
 
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 9ae3517..93746e1 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -2,12 +2,6 @@
 
 def external_plugin_deps():
     maven_jar(
-        name = "tika_core",
-        artifact = "org.apache.tika:tika-core:1.12",
-        sha1 = "5ab95580d22fe1dee79cffbcd98bb509a32da09b",
-    )
-
-    maven_jar(
         name = "commons_io",
         artifact = "commons-io:commons-io:1.4",
         sha1 = "a8762d07e76cfde2395257a5da47ba7c1dbd3dce",
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
index b47d259..d5156f9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
@@ -40,6 +40,7 @@
 import com.google.inject.name.Named;
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.text.MessageFormat;
@@ -52,10 +53,12 @@
 import java.util.concurrent.ExecutionException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import org.eclipse.jgit.diff.RawText;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectLoader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class BlockedKeywordValidator implements CommitValidationListener {
   private static final String KEY_CHECK_BLOCKED_KEYWORD = "blockedKeyword";
@@ -127,7 +130,12 @@
                 Arrays.asList(cfg.getStringList(KEY_CHECK_BLOCKED_KEYWORD_PATTERN)));
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
-              performValidation(repo, receiveEvent.commit, blockedKeywordPatterns.values(), cfg);
+              performValidation(
+                  repo,
+                  receiveEvent.commit,
+                  receiveEvent.revWalk,
+                  blockedKeywordPatterns.values(),
+                  cfg);
           if (!messages.isEmpty()) {
             throw new CommitValidationException(
                 "includes files containing blocked keywords", messages);
@@ -144,16 +152,19 @@
   List<CommitValidationMessage> performValidation(
       Repository repo,
       RevCommit c,
+      RevWalk revWalk,
       ImmutableCollection<Pattern> blockedKeywordPartterns,
       PluginConfig cfg)
       throws IOException, ExecutionException {
     List<CommitValidationMessage> messages = new LinkedList<>();
     checkCommitMessageForBlockedKeywords(blockedKeywordPartterns, messages, c.getFullMessage());
-    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c);
+    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
-      if (contentTypeUtil.isBinary(ol, path, cfg)) {
-        continue;
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
+      try (InputStream in = ol.openStream()) {
+        if (RawText.isBinary(in) || contentTypeUtil.isBlacklistedBinaryContentType(ol, path, cfg)) {
+          continue;
+        }
       }
       checkFileForBlockedKeywords(blockedKeywordPartterns, messages, path, ol);
     }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailValidator.java
new file mode 100644
index 0000000..6deb42c
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailValidator.java
@@ -0,0 +1,155 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.googlesource.gerrit.plugins.uploadvalidator;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Strings;
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.extensions.annotations.PluginName;
+import com.google.gerrit.extensions.api.projects.ProjectConfigEntryType;
+import com.google.gerrit.extensions.registration.DynamicSet;
+import com.google.gerrit.server.config.PluginConfig;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.gerrit.server.config.ProjectConfigEntry;
+import com.google.gerrit.server.events.CommitReceivedEvent;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.validators.CommitValidationException;
+import com.google.gerrit.server.git.validators.CommitValidationListener;
+import com.google.gerrit.server.git.validators.CommitValidationMessage;
+import com.google.gerrit.server.project.NoSuchProjectException;
+import com.google.inject.AbstractModule;
+import com.google.inject.Inject;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Pattern;
+
+public class ChangeEmailValidator implements CommitValidationListener {
+  public static AbstractModule module() {
+    return new AbstractModule() {
+      @Override
+      public void configure() {
+        DynamicSet.bind(binder(), CommitValidationListener.class).to(ChangeEmailValidator.class);
+        bind(ProjectConfigEntry.class)
+            .annotatedWith(Exports.named(KEY_ALLOWED_AUTHOR_EMAIL_PATTERN))
+            .toInstance(
+                new ProjectConfigEntry(
+                    "Author Email Pattern",
+                    null,
+                    ProjectConfigEntryType.ARRAY,
+                    null,
+                    false,
+                    "Commits with author email not matching one of these pattterns will be rejected."));
+        bind(ProjectConfigEntry.class)
+            .annotatedWith(Exports.named(KEY_ALLOWED_COMMITTER_EMAIL_PATTERN))
+            .toInstance(
+                new ProjectConfigEntry(
+                    "Committer Email Pattern",
+                    null,
+                    ProjectConfigEntryType.ARRAY,
+                    null,
+                    false,
+                    "Commits with committer email not matching one of these patterns will be rejected."));
+      }
+    };
+  }
+
+  public static final String KEY_ALLOWED_AUTHOR_EMAIL_PATTERN = "allowedAuthorEmailPattern";
+  public static final String KEY_ALLOWED_COMMITTER_EMAIL_PATTERN = "allowedCommitterEmailPattern";
+  private final String pluginName;
+  private final PluginConfigFactory cfgFactory;
+  private final GitRepositoryManager repoManager;
+  private final ValidatorConfig validatorConfig;
+
+  @Inject
+  ChangeEmailValidator(
+      @PluginName String pluginName,
+      PluginConfigFactory cfgFactory,
+      GitRepositoryManager repoManager,
+      ValidatorConfig validatorConfig) {
+    this.pluginName = pluginName;
+    this.cfgFactory = cfgFactory;
+    this.repoManager = repoManager;
+    this.validatorConfig = validatorConfig;
+  }
+
+  @VisibleForTesting
+  static String[] getAllowedAuthorEmailPatterns(PluginConfig cfg) {
+    return cfg.getStringList(KEY_ALLOWED_AUTHOR_EMAIL_PATTERN);
+  }
+
+  @VisibleForTesting
+  static String[] getAllowedCommitterEmailPatterns(PluginConfig cfg) {
+    return cfg.getStringList(KEY_ALLOWED_COMMITTER_EMAIL_PATTERN);
+  }
+
+  @VisibleForTesting
+  static boolean isAuthorActive(PluginConfig cfg) {
+    return cfg.getStringList(KEY_ALLOWED_AUTHOR_EMAIL_PATTERN).length > 0;
+  }
+
+  @VisibleForTesting
+  static boolean isCommitterActive(PluginConfig cfg) {
+    return cfg.getStringList(KEY_ALLOWED_COMMITTER_EMAIL_PATTERN).length > 0;
+  }
+
+  @Override
+  public List<CommitValidationMessage> onCommitReceived(CommitReceivedEvent receiveEvent)
+      throws CommitValidationException {
+    try {
+      PluginConfig cfg =
+          cfgFactory.getFromProjectConfigWithInheritance(
+              receiveEvent.project.getNameKey(), pluginName);
+      if (isAuthorActive(cfg)
+          && validatorConfig.isEnabledForRef(
+              receiveEvent.user,
+              receiveEvent.getProjectNameKey(),
+              receiveEvent.getRefName(),
+              KEY_ALLOWED_AUTHOR_EMAIL_PATTERN)) {
+        if (!performValidation(
+            receiveEvent.commit.getAuthorIdent().getEmailAddress(),
+            getAllowedAuthorEmailPatterns(cfg))) {
+          throw new CommitValidationException(
+              "Author Email <"
+                  + receiveEvent.commit.getAuthorIdent().getEmailAddress()
+                  + "> - is not allowed for this Project.");
+        }
+      }
+      if (isCommitterActive(cfg)
+          && validatorConfig.isEnabledForRef(
+              receiveEvent.user,
+              receiveEvent.getProjectNameKey(),
+              receiveEvent.getRefName(),
+              KEY_ALLOWED_COMMITTER_EMAIL_PATTERN)) {
+        if (!performValidation(
+            receiveEvent.commit.getCommitterIdent().getEmailAddress(),
+            getAllowedCommitterEmailPatterns(cfg))) {
+          throw new CommitValidationException(
+              "Committer Email <"
+                  + receiveEvent.commit.getCommitterIdent().getEmailAddress()
+                  + "> - is not allowed for this Project.");
+        }
+      }
+    } catch (NoSuchProjectException e) {
+      throw new CommitValidationException("Failed to check for Change Email Patterns ", e);
+    }
+    return Collections.emptyList();
+  }
+
+  @VisibleForTesting
+  static boolean performValidation(String email, String[] allowedEmailPatterns) {
+    return Arrays.stream(allowedEmailPatterns)
+        .anyMatch(s -> Pattern.matches(s, Strings.nullToEmpty(email)));
+  }
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/CommitUtils.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/CommitUtils.java
index 02db4e8..5505343 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/CommitUtils.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/CommitUtils.java
@@ -26,6 +26,7 @@
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.treewalk.filter.TreeFilter;
 
+/** Utility class for checking whether commits are different. */
 public class CommitUtils {
 
   /**
@@ -38,8 +39,9 @@
    *     parents.
    * @throws IOException
    */
-  public static Set<String> getChangedPaths(Repository repo, RevCommit c) throws IOException {
-    Map<String, ObjectId> content = getChangedContent(repo, c);
+  public static Set<String> getChangedPaths(Repository repo, RevCommit c, RevWalk revWalk)
+      throws IOException {
+    Map<String, ObjectId> content = getChangedContent(repo, c, revWalk);
     return content.keySet();
   }
 
@@ -59,13 +61,14 @@
    * @return A Map containing all files which differ between the passed commit and its parents.
    * @throws IOException
    */
-  public static Map<String, ObjectId> getChangedContent(Repository repo, RevCommit c)
-      throws IOException {
+  public static Map<String, ObjectId> getChangedContent(
+      Repository repo, RevCommit c, RevWalk revWalk) throws IOException {
     final Map<String, ObjectId> content = new HashMap<>();
 
     visitChangedEntries(
         repo,
         c,
+        revWalk,
         new TreeWalkVisitor() {
           @Override
           public void onVisit(TreeWalk tw) {
@@ -92,29 +95,18 @@
    * @param visitor A TreeWalkVisitor with the desired action
    * @throws IOException
    */
-  public static void visitChangedEntries(Repository repo, RevCommit c, TreeWalkVisitor visitor)
-      throws IOException {
-    try (TreeWalk tw = new TreeWalk(repo)) {
+  public static void visitChangedEntries(
+      Repository repo, RevCommit c, RevWalk revWalk, TreeWalkVisitor visitor) throws IOException {
+    try (TreeWalk tw = new TreeWalk(revWalk.getObjectReader())) {
       tw.setRecursive(true);
       tw.setFilter(TreeFilter.ANY_DIFF);
       tw.addTree(c.getTree());
       if (c.getParentCount() > 0) {
-        @SuppressWarnings("resource")
-        RevWalk rw = null;
-        try {
-          for (RevCommit p : c.getParents()) {
-            if (p.getTree() == null) {
-              if (rw == null) {
-                rw = new RevWalk(repo);
-              }
-              rw.parseHeaders(p);
-            }
-            tw.addTree(p.getTree());
+        for (RevCommit p : c.getParents()) {
+          if (p.getTree() == null) {
+            revWalk.parseHeaders(p);
           }
-        } finally {
-          if (rw != null) {
-            rw.close();
-          }
+          tw.addTree(p.getTree());
         }
         while (tw.next()) {
           if (isDifferentToAllParents(c, tw)) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtil.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtil.java
index 368a72d..ddb18db 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtil.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtil.java
@@ -22,6 +22,7 @@
 import com.google.gerrit.extensions.api.projects.ProjectConfigEntryType;
 import com.google.gerrit.server.config.PluginConfig;
 import com.google.gerrit.server.config.ProjectConfigEntry;
+import com.google.gerrit.server.mime.FileTypeRegistry;
 import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
 import com.google.inject.name.Named;
@@ -29,10 +30,6 @@
 import java.io.InputStream;
 import java.util.concurrent.ExecutionException;
 import java.util.regex.Pattern;
-import org.apache.tika.Tika;
-import org.apache.tika.config.TikaConfig;
-import org.apache.tika.io.TikaInputStream;
-import org.apache.tika.metadata.Metadata;
 import org.eclipse.jgit.lib.ObjectLoader;
 
 public class ContentTypeUtil {
@@ -68,24 +65,24 @@
   }
 
   private final LoadingCache<String, Pattern> patternCache;
-  private final Tika tika = new Tika(TikaConfig.getDefaultConfig());
+  private final FileTypeRegistry mimeUtil;
 
   @Inject
-  ContentTypeUtil(@Named(CACHE_NAME) LoadingCache<String, Pattern> patternCache) {
+  ContentTypeUtil(
+      @Named(CACHE_NAME) LoadingCache<String, Pattern> patternCache, FileTypeRegistry mimeUtil) {
     this.patternCache = patternCache;
+    this.mimeUtil = mimeUtil;
   }
 
-  public boolean isBinary(ObjectLoader ol, String pathname, PluginConfig cfg)
+  public boolean isBlacklistedBinaryContentType(ObjectLoader ol, String pathname, PluginConfig cfg)
       throws IOException, ExecutionException {
-    try (InputStream is = ol.openStream()) {
-      return matchesAny(getContentType(is, pathname), getBinaryTypes(cfg));
-    }
+    return matchesAny(getContentType(ol, pathname), getBinaryTypes(cfg));
   }
 
-  public String getContentType(InputStream is, String pathname) throws IOException {
-    Metadata metadata = new Metadata();
-    metadata.set(Metadata.RESOURCE_NAME_KEY, pathname);
-    return tika.detect(TikaInputStream.get(is), metadata);
+  public String getContentType(ObjectLoader ol, String pathname) throws IOException {
+    try (InputStream is = ol.openStream()) {
+      return mimeUtil.getMimeType(pathname, is).toString();
+    }
   }
 
   @VisibleForTesting
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
index 8893f00..1cc5fd4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
@@ -38,9 +38,9 @@
 import java.util.concurrent.ExecutionException;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectLoader;
-import org.eclipse.jgit.lib.ObjectStream;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class ContentTypeValidator implements CommitValidationListener {
 
@@ -129,7 +129,12 @@
               KEY_BLOCKED_CONTENT_TYPE)) {
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
-              performValidation(repo, receiveEvent.commit, getBlockedTypes(cfg), isWhitelist(cfg));
+              performValidation(
+                  repo,
+                  receiveEvent.commit,
+                  receiveEvent.revWalk,
+                  getBlockedTypes(cfg),
+                  isWhitelist(cfg));
           if (!messages.isEmpty()) {
             throw new CommitValidationException("contains blocked content type", messages);
           }
@@ -143,20 +148,18 @@
 
   @VisibleForTesting
   List<CommitValidationMessage> performValidation(
-      Repository repo, RevCommit c, String[] blockedTypes, boolean whitelist)
+      Repository repo, RevCommit c, RevWalk revWalk, String[] blockedTypes, boolean whitelist)
       throws IOException, ExecutionException {
     List<CommitValidationMessage> messages = new LinkedList<>();
-    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c);
+    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
-      try (ObjectStream os = ol.openStream()) {
-        String contentType = contentTypeUtil.getContentType(os, path);
-        if ((contentTypeUtil.matchesAny(contentType, blockedTypes) && !whitelist)
-            || (!contentTypeUtil.matchesAny(contentType, blockedTypes) && whitelist)) {
-          messages.add(
-              new CommitValidationMessage(
-                  "found blocked content type (" + contentType + ") in file: " + path, true));
-        }
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
+      String contentType = contentTypeUtil.getContentType(ol, path);
+      if ((contentTypeUtil.matchesAny(contentType, blockedTypes) && !whitelist)
+          || (!contentTypeUtil.matchesAny(contentType, blockedTypes) && whitelist)) {
+        messages.add(
+            new CommitValidationMessage(
+                "found blocked content type (" + contentType + ") in file: " + path, true));
       }
     }
     return messages;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidator.java
index c89326e..0b93e6d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidator.java
@@ -47,6 +47,7 @@
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 
 public class DuplicatePathnameValidator implements CommitValidationListener {
@@ -187,7 +188,8 @@
               KEY_REJECT_DUPLICATE_PATHNAMES)) {
         locale = getLocale(cfg);
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
-          List<CommitValidationMessage> messages = performValidation(repo, receiveEvent.commit);
+          List<CommitValidationMessage> messages =
+              performValidation(repo, receiveEvent.commit, receiveEvent.revWalk);
           if (!messages.isEmpty()) {
             throw new CommitValidationException("contains duplicate pathnames", messages);
           }
@@ -200,10 +202,11 @@
   }
 
   @VisibleForTesting
-  List<CommitValidationMessage> performValidation(Repository repo, RevCommit c) throws IOException {
+  List<CommitValidationMessage> performValidation(Repository repo, RevCommit c, RevWalk revWalk)
+      throws IOException {
     List<CommitValidationMessage> messages = new LinkedList<>();
 
-    Set<String> pathnames = CommitUtils.getChangedPaths(repo, c);
+    Set<String> pathnames = CommitUtils.getChangedPaths(repo, c, revWalk);
     checkForDuplicatesInSet(pathnames, messages);
     if (!messages.isEmpty() || c.getParentCount() == 0) {
       return messages;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidator.java
index f3652c7..716f32e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidator.java
@@ -36,6 +36,7 @@
 import java.util.List;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class FileExtensionValidator implements CommitValidationListener {
 
@@ -106,7 +107,8 @@
               KEY_BLOCKED_FILE_EXTENSION)) {
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
-              performValidation(repo, receiveEvent.commit, getBlockedExtensions(cfg));
+              performValidation(
+                  repo, receiveEvent.commit, receiveEvent.revWalk, getBlockedExtensions(cfg));
           if (!messages.isEmpty()) {
             throw new CommitValidationException(
                 "contains files with blocked file extensions", messages);
@@ -120,9 +122,10 @@
   }
 
   static List<CommitValidationMessage> performValidation(
-      Repository repo, RevCommit c, List<String> blockedFileExtensions) throws IOException {
+      Repository repo, RevCommit c, RevWalk revWalk, List<String> blockedFileExtensions)
+      throws IOException {
     List<CommitValidationMessage> messages = new LinkedList<>();
-    for (String file : CommitUtils.getChangedPaths(repo, c)) {
+    for (String file : CommitUtils.getChangedPaths(repo, c, revWalk)) {
       for (String blockedExtension : blockedFileExtensions) {
         if (file.toLowerCase().endsWith(blockedExtension.toLowerCase())) {
           messages.add(new CommitValidationMessage("blocked file: " + file, true));
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidator.java
index ac914d5..846288f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidator.java
@@ -37,6 +37,7 @@
 import java.util.regex.Pattern;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class InvalidFilenameValidator implements CommitValidationListener {
 
@@ -102,7 +103,10 @@
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
               performValidation(
-                  repo, receiveEvent.commit, cfg.getStringList(KEY_INVALID_FILENAME_PATTERN));
+                  repo,
+                  receiveEvent.commit,
+                  receiveEvent.revWalk,
+                  cfg.getStringList(KEY_INVALID_FILENAME_PATTERN));
           if (!messages.isEmpty()) {
             throw new CommitValidationException(
                 "contains files with an invalid filename", messages);
@@ -116,13 +120,13 @@
   }
 
   static List<CommitValidationMessage> performValidation(
-      Repository repo, RevCommit c, String[] patterns) throws IOException {
+      Repository repo, RevCommit c, RevWalk revWalk, String[] patterns) throws IOException {
     List<Pattern> invalidFilenamePatterns = new ArrayList<>();
     for (String s : patterns) {
       invalidFilenamePatterns.add(Pattern.compile(s));
     }
     List<CommitValidationMessage> messages = new LinkedList<>();
-    for (String file : CommitUtils.getChangedPaths(repo, c)) {
+    for (String file : CommitUtils.getChangedPaths(repo, c, revWalk)) {
       for (Pattern p : invalidFilenamePatterns) {
         if (p.matcher(file).find()) {
           messages.add(
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
index 95fb586..2f602b0 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
@@ -31,6 +31,7 @@
 import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.util.Collections;
@@ -38,10 +39,12 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
+import org.eclipse.jgit.diff.RawText;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectLoader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class InvalidLineEndingValidator implements CommitValidationListener {
 
@@ -109,7 +112,7 @@
               KEY_CHECK_REJECT_WINDOWS_LINE_ENDINGS)) {
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
-              performValidation(repo, receiveEvent.commit, cfg);
+              performValidation(repo, receiveEvent.commit, receiveEvent.revWalk, cfg);
           if (!messages.isEmpty()) {
             throw new CommitValidationException(
                 "contains files with a Windows line ending", messages);
@@ -123,14 +126,17 @@
   }
 
   @VisibleForTesting
-  List<CommitValidationMessage> performValidation(Repository repo, RevCommit c, PluginConfig cfg)
+  List<CommitValidationMessage> performValidation(
+      Repository repo, RevCommit c, RevWalk revWalk, PluginConfig cfg)
       throws IOException, ExecutionException {
     List<CommitValidationMessage> messages = new LinkedList<>();
-    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c);
+    Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
-      if (contentTypeUtil.isBinary(ol, path, cfg)) {
-        continue;
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
+      try (InputStream in = ol.openStream()) {
+        if (RawText.isBinary(in) || contentTypeUtil.isBlacklistedBinaryContentType(ol, path, cfg)) {
+          continue;
+        }
       }
       try (InputStreamReader isr = new InputStreamReader(ol.openStream(), StandardCharsets.UTF_8)) {
         if (doesInputStreanContainCR(isr)) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidator.java
index 2899613..2216451 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidator.java
@@ -34,6 +34,7 @@
 import java.util.List;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class MaxPathLengthValidator implements CommitValidationListener {
 
@@ -96,7 +97,7 @@
         int maxPathLength = cfg.getInt(KEY_MAX_PATH_LENGTH, 0);
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
           List<CommitValidationMessage> messages =
-              performValidation(repo, receiveEvent.commit, maxPathLength);
+              performValidation(repo, receiveEvent.commit, receiveEvent.revWalk, maxPathLength);
           if (!messages.isEmpty()) {
             throw new CommitValidationException(
                 "contains files with too long paths (max path length: " + maxPathLength + ")",
@@ -111,9 +112,9 @@
   }
 
   static List<CommitValidationMessage> performValidation(
-      Repository repo, RevCommit c, int maxPathLength) throws IOException {
+      Repository repo, RevCommit c, RevWalk revWalk, int maxPathLength) throws IOException {
     List<CommitValidationMessage> messages = new LinkedList<>();
-    for (String file : CommitUtils.getChangedPaths(repo, c)) {
+    for (String file : CommitUtils.getChangedPaths(repo, c, revWalk)) {
       if (file.length() > maxPathLength) {
         messages.add(new CommitValidationMessage("path too long: " + file, true));
       }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/Module.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/Module.java
index 5b6677a..e15ecb2 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/Module.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/Module.java
@@ -27,6 +27,7 @@
     install(FooterValidator.module());
     install(MaxPathLengthValidator.module());
     install(FileExtensionValidator.module());
+    install(ChangeEmailValidator.module());
     install(InvalidFilenameValidator.module());
     install(SubmoduleValidator.module());
     install(SymlinkValidator.module());
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidator.java
index 9e4a31c..08d4d3f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidator.java
@@ -36,6 +36,7 @@
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 
 public class SubmoduleValidator implements CommitValidationListener {
@@ -97,7 +98,8 @@
               receiveEvent.getRefName(),
               KEY_CHECK_SUBMODULE)) {
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
-          List<CommitValidationMessage> messages = performValidation(repo, receiveEvent.commit);
+          List<CommitValidationMessage> messages =
+              performValidation(repo, receiveEvent.commit, receiveEvent.revWalk);
           if (!messages.isEmpty()) {
             throw new CommitValidationException("contains submodules", messages);
           }
@@ -118,13 +120,14 @@
     return (tw.getRawMode(0) & FileMode.TYPE_MASK) == FileMode.TYPE_GITLINK;
   }
 
-  static List<CommitValidationMessage> performValidation(Repository repo, RevCommit c)
-      throws IOException {
+  static List<CommitValidationMessage> performValidation(
+      Repository repo, RevCommit c, RevWalk revWalk) throws IOException {
     final List<CommitValidationMessage> messages = new LinkedList<>();
 
     CommitUtils.visitChangedEntries(
         repo,
         c,
+        revWalk,
         new TreeWalkVisitor() {
           @Override
           public void onVisit(TreeWalk tw) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidator.java
index 057efff..7b7d893 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidator.java
@@ -36,6 +36,7 @@
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 
 public class SymlinkValidator implements CommitValidationListener {
@@ -98,7 +99,8 @@
               receiveEvent.getRefName(),
               KEY_CHECK_SYMLINK)) {
         try (Repository repo = repoManager.openRepository(receiveEvent.project.getNameKey())) {
-          List<CommitValidationMessage> messages = performValidation(repo, receiveEvent.commit);
+          List<CommitValidationMessage> messages =
+              performValidation(repo, receiveEvent.commit, receiveEvent.revWalk);
           if (!messages.isEmpty()) {
             throw new CommitValidationException("contains symbolic links", messages);
           }
@@ -119,13 +121,14 @@
     return (tw.getRawMode(0) & FileMode.TYPE_MASK) == FileMode.TYPE_SYMLINK;
   }
 
-  static List<CommitValidationMessage> performValidation(Repository repo, RevCommit c)
-      throws IOException {
+  static List<CommitValidationMessage> performValidation(
+      Repository repo, RevCommit c, RevWalk revWalk) throws IOException {
     final List<CommitValidationMessage> messages = new LinkedList<>();
 
     CommitUtils.visitChangedEntries(
         repo,
         c,
+        revWalk,
         new TreeWalkVisitor() {
           @Override
           public void onVisit(TreeWalk tw) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ValidatorConfig.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ValidatorConfig.java
index e30e177..c4ae334 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ValidatorConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ValidatorConfig.java
@@ -14,19 +14,24 @@
 
 package com.googlesource.gerrit.plugins.uploadvalidator;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.RefConfigSection;
 import com.google.gerrit.extensions.annotations.Exports;
 import com.google.gerrit.extensions.api.projects.ProjectConfigEntryType;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.IdentifiedUser;
-import com.google.gerrit.server.account.GroupCache;
 import com.google.gerrit.server.config.PluginConfig;
 import com.google.gerrit.server.config.ProjectConfigEntry;
+import com.google.gerrit.server.group.InternalGroup;
 import com.google.gerrit.server.project.RefPatternMatcher;
+import com.google.gerrit.server.query.group.InternalGroupQuery;
+import com.google.gwtorm.server.OrmException;
 import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
+import com.google.inject.Provider;
 import java.util.Arrays;
+import java.util.Optional;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 import org.slf4j.Logger;
@@ -37,7 +42,7 @@
   private static final String KEY_PROJECT = "project";
   private static final String KEY_REF = "ref";
   private final ConfigFactory configFactory;
-  private final GroupCache groupCache;
+  private final GroupByNameFinder groupByNameFinder;
 
   public static AbstractModule module() {
     return new AbstractModule() {
@@ -63,14 +68,15 @@
                     null,
                     false,
                     "Only refs that match this regex will be validated."));
+        bind(GroupByNameFinder.class).to(GroupByNameFromIndexFinder.class);
       }
     };
   }
 
   @Inject
-  public ValidatorConfig(ConfigFactory configFactory, GroupCache groupCache) {
+  public ValidatorConfig(ConfigFactory configFactory, GroupByNameFinder groupByNameFinder) {
     this.configFactory = configFactory;
-    this.groupCache = groupCache;
+    this.groupByNameFinder = groupByNameFinder;
   }
 
   public boolean isEnabledForRef(
@@ -121,7 +127,7 @@
     return matchCriteria(config, "ref", ref, true, true);
   }
 
-  private boolean activeForEmail(PluginConfig config, String email) {
+  private boolean activeForEmail(PluginConfig config, @Nullable String email) {
     return matchCriteria(config, "email", email, true, false);
   }
 
@@ -134,15 +140,22 @@
   }
 
   private boolean matchCriteria(
-      PluginConfig config, String criteria, String value, boolean allowRegex, boolean refMatcher) {
-    boolean match = true;
-    for (String s : config.getStringList(criteria)) {
-      if ((allowRegex && match(value, s, refMatcher)) || (!allowRegex && s.equals(value))) {
-        return true;
-      }
-      match = false;
+      PluginConfig config,
+      String criteria,
+      @Nullable String value,
+      boolean allowRegex,
+      boolean refMatcher) {
+    String[] c = config.getStringList(criteria);
+    if (c.length == 0) {
+      return true;
     }
-    return match;
+    if (value == null) {
+      return false;
+    }
+    if (allowRegex) {
+      return Arrays.stream(c).anyMatch(s -> match(value, s, refMatcher));
+    }
+    return Arrays.asList(c).contains(value);
   }
 
   private static boolean match(String value, String pattern, boolean refMatcher) {
@@ -163,10 +176,32 @@
   }
 
   private AccountGroup.UUID groupUUID(String groupNameOrUUID) {
-    AccountGroup group = groupCache.get(new AccountGroup.NameKey(groupNameOrUUID));
-    if (group == null) {
-      return new AccountGroup.UUID(groupNameOrUUID);
+    Optional<InternalGroup> group =
+        groupByNameFinder.get(new AccountGroup.NameKey(groupNameOrUUID));
+    return group.map(InternalGroup::getGroupUUID).orElse(new AccountGroup.UUID(groupNameOrUUID));
+  }
+
+  interface GroupByNameFinder {
+    Optional<InternalGroup> get(AccountGroup.NameKey groupName);
+  }
+
+  static class GroupByNameFromIndexFinder implements GroupByNameFinder {
+
+    private final Provider<InternalGroupQuery> groupQueryProvider;
+
+    @Inject
+    GroupByNameFromIndexFinder(Provider<InternalGroupQuery> groupQueryProvider) {
+      this.groupQueryProvider = groupQueryProvider;
     }
-    return group.getGroupUUID();
+
+    @Override
+    public Optional<InternalGroup> get(AccountGroup.NameKey groupName) {
+      try {
+        return groupQueryProvider.get().byName(groupName);
+      } catch (OrmException e) {
+        log.warn(String.format("Cannot lookup group %s by name", groupName.get()), e);
+      }
+      return Optional.empty();
+    }
   }
 }
diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
index 5e4fdf3..67da3ad 100644
--- a/src/main/resources/Documentation/about.md
+++ b/src/main/resources/Documentation/about.md
@@ -12,5 +12,6 @@
 - reject submodules
 - required footers
 - maximum allowed path length
+- allowing committer and author email addresses
 
 Pushes of commits that violate these settings are rejected by Gerrit.
diff --git a/src/main/resources/Documentation/build.md b/src/main/resources/Documentation/build.md
index 9c20e5c..20b8cd1 100644
--- a/src/main/resources/Documentation/build.md
+++ b/src/main/resources/Documentation/build.md
@@ -60,15 +60,6 @@
   ln -s ../../@PLUGIN@ .
 ```
 
-Put the external dependency Bazel build file into the Gerrit /plugins
-directory, replacing the existing empty one.
-
-```
-  cd gerrit/plugins
-  rm external_plugin_deps.bzl
-  ln -s @PLUGIN@/external_plugin_deps.bzl .
-```
-
 From Gerrit source tree issue the command:
 
 ```
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 04c04a1..95c6775 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -32,156 +32,189 @@
     rejectSubmodule = false
     rejectDuplicatePathnames = false
     rejectDuplicatePathnamesLocale = en
+    allowedAuthorEmailPattern = .*@example\\.com$
+    allowedAuthorEmailPattern = admin@example\\.com
+    allowedCommitterEmailPattern = .*gerrit\\.com
+    allowedCommitterEmailPattern =  admin@gerrit\\..*
 ```
 
-plugin.@PLUGIN@.blockedFileExtension
-:	File extension to be blocked.
+plugin.@PLUGIN@.allowedAuthorEmailPattern
+:    Author Email to Allow.
 
-	The values for this check are case insensitive. You can define the
-	blocked file extensions with or without a leading dot. This check
-	only test if the filename ends with one of the defined values.
+    The check looks for a match based on the described specifics.
+    If there are no matches the push will be rejected.
+
+    Note that all email addresses contain the dot character, and if
+    included in the pattern needs to be properly escaped as shown in
+    the examples.
+
+    This check is using `java.util.regex.Pattern` which is described
+    [here][1].
+
+plugin.@PLUGIN@.allowedCommitterEmailPattern
+:    Committer Email to Allow.
+
+    The check looks for a match based on the described specifics.
+    If there are no matches the push will be rejected.
+
+    Note that all email addresses contain the dot character, and if
+    included in the pattern needs to be properly escaped as shown in
+    the examples.
+
+    This check is using `java.util.regex.Pattern` which is described
+    [here][1].
+
+plugin.@PLUGIN@.blockedFileExtension
+:    File extension to be blocked.
+
+    The values for this check are case insensitive. You can define the
+    blocked file extensions with or without a leading dot. This check
+    only test if the filename ends with one of the defined values.
 
 plugin.@PLUGIN@.requiredFooter
-:	Footer that is required.
+:    Footer that is required.
 
-	This is the footer in the commit message.
+    This is the footer in the commit message.
 
 plugin.@PLUGIN@.maxPathLength
-:	Maximum allowed path length. '0' means no limit.
+:    Maximum allowed path length. '0' means no limit.
 
-	Defaults to '0'.
+    Defaults to '0'.
 
 plugin.@PLUGIN@.invalidFilenamePattern
-:	Patterns for invalid filenames.
+:    Patterns for invalid filenames.
 
-	This check is using `java.util.regex.Pattern` which is described
-	[here][1].
+    This check is using `java.util.regex.Pattern` which is described
+    [here][1].
 
 plugin.@PLUGIN@.rejectWindowsLineEndings
-:	Reject Windows line endings.
+:    Reject Windows line endings.
 
-	This check looks for carriage return (CR) characters in pushed
-	files. If the check finds a carriage return (CR) character
-	the push will be rejected.
+    This check looks for carriage return (CR) characters in pushed
+    files. If the check finds a carriage return (CR) character
+    the push will be rejected.
 
-	This check does not run on [binary files][4]
+    This check does not run on [binary files][4]
 
-	The default value is false. This means the check will not be executed.
+    The default value is false. This means the check will not be executed.
 
 <a name="binary_type">
 plugin.@PLUGIN@.binaryType
-:	Binary types.
+:    Binary types.
 
-	Some checks should not run on binary files (e. g. InvalidLineEndingCheck).
-	Using this option it is possible to configure which content types are
-	considered binary types.
+    Some checks should not run on binary files (e. g. InvalidLineEndingCheck).
+    Using this option it is possible to configure which content types are
+    considered binary types.
 
-	To detect content types [Apache Tika library][2] is used.
+    If there is a NUL byte in the first 8k then the file will be considered
+    binary regardless of this setting.
 
-	Content type can be specified as a string, wildcard or a regular expression,
-	for example:
+    To detect content types, the [MimeUtil2 library][2] is used.
 
-	- application/zip
-	- application/*
-	- ^application/(pdf|xml)
+    Content type can be specified as a string, wildcard or a regular expression,
+    for example:
 
-	As usual, the '^' prefix is used to denote that the value is a regular
-	expression.
+    - application/zip
+    - application/*
+    - ^application/(pdf|xml)
 
-	Full list of supported content types can be found [here][3].
+    As usual, the '^' prefix is used to denote that the value is a regular
+    expression.
+
+    Full list of supported content types can be found [here][3].
 
 plugin.@PLUGIN@.rejectSymlink
-:	Reject symbolic links.
+:    Reject symbolic links.
 
-	This check looks for symbolic links in the set of pushed files. If
-	the check finds a symbolic link the push will be rejected.
+    This check looks for symbolic links in the set of pushed files. If
+    the check finds a symbolic link the push will be rejected.
 
-	The default value is false. This means the check will not be executed.
+    The default value is false. This means the check will not be executed.
 
 plugin.@PLUGIN@.rejectSubmodule
-:	Reject submodules.
+:    Reject submodules.
 
-	This check looks for submodules in the set of pushed commits. If
-	the check finds a submodule the push will be rejected.
+    This check looks for submodules in the set of pushed commits. If
+    the check finds a submodule the push will be rejected.
 
-	The default value is false. This means the check will not be executed.
+    The default value is false. This means the check will not be executed.
 
 plugin.@PLUGIN@.blockedKeywordPattern
-:	Patterns for blocked keywords.
+:    Patterns for blocked keywords.
 
-	This check looks for blocked keywords in files. If the check finds an
-	blocked keyword the push will be rejected.
+    This check looks for blocked keywords in files. If the check finds an
+    blocked keyword the push will be rejected.
 
-	To find a keyword it is possible to pass a regular expressions by
-	blockedKeywordPattern.
+    To find a keyword it is possible to pass a regular expressions by
+    blockedKeywordPattern.
 
-	To detect blocked keywords, this check is using
-	`java.util.regex.Pattern` which is described [here][1].
+    To detect blocked keywords, this check is using
+    `java.util.regex.Pattern` which is described [here][1].
 
-	This check does not run on [binary files][4]
+    This check does not run on [binary files][4]
 
 [1]: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html
-[2]: https://tika.apache.org/
-[3]: https://tika.apache.org/1.12/formats.html#Full_list_of_Supported_Formats
+[2]: https://mvnrepository.com/artifact/eu.medsea.mimeutil/mime-util
+[3]: https://gerrit.googlesource.com/gerrit/+/refs/heads/master/gerrit-server/src/main/resources/com/google/gerrit/server/mime/mime-types.properties
 [4]: #binary_type
 
 plugin.@PLUGIN@.blockedContentType
-:	Blocked content type.
+:    Blocked content type.
 
-	This check looks for blocked content types. If the check finds a
-	blocked content type the push will be rejected.
+    This check looks for blocked content types. If the check finds a
+    blocked content type the push will be rejected.
 
-	To detect content types [Apache Tika library][2] is used.
+    To detect content types the [MimeUtil2 library][2] is used.
 
-	Content type can be specified as a string, wildcard or a regular expression,
-	for example:
+    Content type can be specified as a string, wildcard or a regular expression,
+    for example:
 
-	- application/zip
-	- application/*
-	- ^application/(pdf|xml)
+    - application/zip
+    - application/*
+    - ^application/(pdf|xml)
 
-	As usual, the '^' prefix is used to denote that the value is a regular
-	expression.
+    As usual, the '^' prefix is used to denote that the value is a regular
+    expression.
 
-	Full list of supported content types can be found [here][3].
+    Full list of supported content types can be found [here][3].
 
 plugin.@PLUGIN@.blockedContentTypeWhitelist
-:	Blocked content type whitelist.
+:    Blocked content type whitelist.
 
-	If this option is checked, the entered content types are interpreted as
-	a whitelist. Otherwise the entered content types are interpreted as a
-	blacklist and commits that contains one of these content types will be
-	rejected.
+    If this option is checked, the entered content types are interpreted as
+    a whitelist. Otherwise the entered content types are interpreted as a
+    blacklist and commits that contains one of these content types will be
+    rejected.
 
-	There must be specified at least one blocked content type pattern,
-	otherwise this option will be ignored.
+    There must be specified at least one blocked content type pattern,
+    otherwise this option will be ignored.
 
-	The default value is false. This means the entered content types are
-	interpreted as a blacklist.
+    The default value is false. This means the entered content types are
+    interpreted as a blacklist.
 
 plugin.@PLUGIN@.rejectDuplicatePathnames
-:	Reject duplicate pathnames.
+:    Reject duplicate pathnames.
 
-	This check looks for duplicate pathnames which only differ in case
-	in the tree of the commit as these can cause problems on case
-	insensitive filesystems commonly used e.g. on Windows or Mac. If the
-	check finds duplicate pathnames the push will be rejected.
+    This check looks for duplicate pathnames which only differ in case
+    in the tree of the commit as these can cause problems on case
+    insensitive filesystems commonly used e.g. on Windows or Mac. If the
+    check finds duplicate pathnames the push will be rejected.
 
-	The default value is false. This means duplicate pathnames ignoring
-	case are allowed.
+    The default value is false. This means duplicate pathnames ignoring
+    case are allowed.
 
 plugin.@PLUGIN@.rejectDuplicatePathnamesLocale
-:	Reject duplicate pathnames locale.
+:    Reject duplicate pathnames locale.
 
-	When the validator checks for duplicate pathnames it will convert
-	the pathnames to lower case. In some cases this leads to a [problem][5].
+    When the validator checks for duplicate pathnames it will convert
+    the pathnames to lower case. In some cases this leads to a [problem][5].
 
-	To avoid these kind of problems, this option is used to specify a
-	locale which is used when converting a pathname to lower case.
+    To avoid these kind of problems, this option is used to specify a
+    locale which is used when converting a pathname to lower case.
 
-	Full list of supported locales can be found [here][6].
+    Full list of supported locales can be found [here][6].
 
-	The default value is "en" (English).
+    The default value is "en" (English).
 
 [5]: http://bugs.java.com/view_bug.do?bug_id=6208680
 [6]: http://www.oracle.com/technetwork/java/javase/javase7locales-334809.html
@@ -267,47 +300,47 @@
 Skip of the rules is controlled by:
 
 plugin.@PLUGIN@.skipGroup
-:	Group names or UUIDs allowed to skip the rules.
+:    Group names or UUIDs allowed to skip the rules.
 
-	Groups that are allowed to skip the rules.
+    Groups that are allowed to skip the rules.
 
-	Multiple values are supported.
-	Default: nobody is allowed to skip the rules (empty).
+    Multiple values are supported.
+    Default: nobody is allowed to skip the rules (empty).
 
-	NOTE: When skipGroup isn't defined, all the other skip settings are ignored.
+    NOTE: When skipGroup isn't defined, all the other skip settings are ignored.
 
 plugin.@PLUGIN@.skipRef
-:	Ref name, pattern or regexp of the branch to skip.
+:    Ref name, pattern or regexp of the branch to skip.
 
-	List of specific ref names, ref patterns, or regular expressions
-	of the branches where Groups defined in skipGroup are allowed to
-	skip the rules.
+    List of specific ref names, ref patterns, or regular expressions
+    of the branches where Groups defined in skipGroup are allowed to
+    skip the rules.
 
-	Multiple values are supported.
-	Default: skip validation on all branches for commits pushed by a member of
-	a group listed in skipGroup
+    Multiple values are supported.
+    Default: skip validation on all branches for commits pushed by a member of
+    a group listed in skipGroup
 
 plugin.@PLUGIN@.skipValidation
-:	Specific validation to be skipped.
+:    Specific validation to be skipped.
 
-	List of specific validation operations allowed to be skipped by
-	the Groups defined in skipGroup on the branches defined in skipRef.
+    List of specific validation operations allowed to be skipped by
+    the Groups defined in skipGroup on the branches defined in skipRef.
 
-	Validations can be one of the following strings:
+    Validations can be one of the following strings:
 
-	- blockedContentType
-	- blockedFileExtension
-	- blockedKeyword
-	- invalidFilename
-	- maxPathLength
-	- rejectDuplicatePathnames
-	- rejectSubmodule
-	- rejectSymlink
-	- rejectWindowsLineEndings
-	- requiredFooter
+    - blockedContentType
+    - blockedFileExtension
+    - blockedKeyword
+    - invalidFilename
+    - maxPathLength
+    - rejectDuplicatePathnames
+    - rejectSubmodule
+    - rejectSymlink
+    - rejectWindowsLineEndings
+    - requiredFooter
 
-	Multiple values are supported.
-	Default: groups defined at skipGroup can skip all the validation rules.
+    Multiple values are supported.
+    Default: groups defined at skipGroup can skip all the validation rules.
 
 NOTE: Skip of the validations are inherited from parent projects. The definition
 of the skip criteria on All-Projects automatically apply to every project.
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidatorTest.java
index 609cf72..20f2e83 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidatorTest.java
@@ -32,6 +32,7 @@
 import java.util.regex.Pattern;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class BlockedKeywordValidatorTest extends ValidatorTestCase {
@@ -43,7 +44,7 @@
         .build();
   }
 
-  private RevCommit makeCommit() throws IOException, GitAPIException {
+  private RevCommit makeCommit(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
     // invalid files
     String content = "http://foo.bar.tld/?pw=myp4ssw0rdTefoobarstline2\n";
@@ -66,26 +67,33 @@
     files.put(
         new File(repo.getDirectory().getParent(), "foobar.txt"),
         content.getBytes(StandardCharsets.UTF_8));
-    return TestUtils.makeCommit(repo, "Commit foobar with test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit foobar with test files.", files);
   }
 
   @Test
   public void testKeywords() throws Exception {
-    RevCommit c = makeCommit();
-    BlockedKeywordValidator validator =
-        new BlockedKeywordValidator(
-            null, new ContentTypeUtil(PATTERN_CACHE), PATTERN_CACHE, null, null, null);
-    List<CommitValidationMessage> m =
-        validator.performValidation(repo, c, getPatterns().values(), EMPTY_PLUGIN_CONFIG);
-    Set<String> expected =
-        ImmutableSet.of(
-            "ERROR: blocked keyword(s) found in: foo.txt (Line: 1)"
-                + " (found: myp4ssw0rd, foobar)",
-            "ERROR: blocked keyword(s) found in: bar.txt (Line: 5)" + " (found: $Id: foo bar$)",
-            "ERROR: blocked keyword(s) found in: "
-                + Patch.COMMIT_MSG
-                + " (Line: 1) (found: foobar)");
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw);
+      BlockedKeywordValidator validator =
+          new BlockedKeywordValidator(
+              null,
+              new ContentTypeUtil(PATTERN_CACHE, new FakeMimeUtilFileTypeRegistry()),
+              PATTERN_CACHE,
+              null,
+              null,
+              null);
+      List<CommitValidationMessage> m =
+          validator.performValidation(repo, c, rw, getPatterns().values(), EMPTY_PLUGIN_CONFIG);
+      Set<String> expected =
+          ImmutableSet.of(
+              "ERROR: blocked keyword(s) found in: foo.txt (Line: 1)"
+                  + " (found: myp4ssw0rd, foobar)",
+              "ERROR: blocked keyword(s) found in: bar.txt (Line: 5)" + " (found: $Id: foo bar$)",
+              "ERROR: blocked keyword(s) found in: "
+                  + Patch.COMMIT_MSG
+                  + " (Line: 1) (found: foobar)");
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    }
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailTest.java
new file mode 100644
index 0000000..0b208f2
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ChangeEmailTest.java
@@ -0,0 +1,81 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.uploadvalidator;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.googlesource.gerrit.plugins.uploadvalidator.TestUtils.EMPTY_PLUGIN_CONFIG;
+
+import org.junit.Test;
+
+public class ChangeEmailTest {
+  private static final String[] allowedEmailPatterns = {
+    ".*@example\\.com.*",
+    "testing\\.com",
+    "tester@testing\\.com",
+    ".*google\\.com",
+    "tester@gerrit\\..*"
+  };
+
+  @Test
+  public void testEmailValid() throws Exception {
+    assertThat(
+            ChangeEmailValidator.performValidation("tester@example.com.net", allowedEmailPatterns))
+        .isTrue();
+    assertThat(ChangeEmailValidator.performValidation("tester@testing.com", allowedEmailPatterns))
+        .isTrue();
+    assertThat(ChangeEmailValidator.performValidation("tester@google.com", allowedEmailPatterns))
+        .isTrue();
+    assertThat(ChangeEmailValidator.performValidation("tester@gerrit.net", allowedEmailPatterns))
+        .isTrue();
+  }
+
+  @Test
+  public void testEmailInvalid() throws Exception {
+    assertThat(ChangeEmailValidator.performValidation("tester@example.org", allowedEmailPatterns))
+        .isFalse();
+    assertThat(ChangeEmailValidator.performValidation("test@testing.com", allowedEmailPatterns))
+        .isFalse();
+    assertThat(
+            ChangeEmailValidator.performValidation("tester@google.com.net", allowedEmailPatterns))
+        .isFalse();
+    assertThat(
+            ChangeEmailValidator.performValidation(
+                "emailtester@gerritnet.com", allowedEmailPatterns))
+        .isFalse();
+  }
+
+  @Test
+  public void testEmailNull() throws Exception {
+    assertThat(ChangeEmailValidator.performValidation(null, allowedEmailPatterns)).isFalse();
+  }
+
+  @Test
+  public void testEmailEmpty() throws Exception {
+    assertThat(ChangeEmailValidator.performValidation("", allowedEmailPatterns)).isFalse();
+  }
+
+  @Test
+  public void validatorBehaviorWhenAuthorConfigEmpty() {
+    assertThat(ChangeEmailValidator.isAuthorActive(EMPTY_PLUGIN_CONFIG)).isFalse();
+    assertThat(ChangeEmailValidator.getAllowedAuthorEmailPatterns(EMPTY_PLUGIN_CONFIG)).isEmpty();
+  }
+
+  @Test
+  public void validatorBehaviorWhenCommitterConfigEmpty() {
+    assertThat(ChangeEmailValidator.isCommitterActive(EMPTY_PLUGIN_CONFIG)).isFalse();
+    assertThat(ChangeEmailValidator.getAllowedCommitterEmailPatterns(EMPTY_PLUGIN_CONFIG))
+        .isEmpty();
+  }
+}
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtilTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtilTest.java
index 91df4c6..a8e2713 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtilTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeUtilTest.java
@@ -18,16 +18,19 @@
 import static com.googlesource.gerrit.plugins.uploadvalidator.TestUtils.EMPTY_PLUGIN_CONFIG;
 import static com.googlesource.gerrit.plugins.uploadvalidator.TestUtils.PATTERN_CACHE;
 
+import com.google.gerrit.server.mime.MimeUtilFileTypeRegistry;
+import com.google.inject.Inject;
 import java.util.concurrent.ExecutionException;
 import org.junit.Before;
 import org.junit.Test;
 
 public class ContentTypeUtilTest {
   private ContentTypeUtil ctu;
+  @Inject private MimeUtilFileTypeRegistry mimeUtil;
 
   @Before
   public void setUp() {
-    ctu = new ContentTypeUtil(PATTERN_CACHE);
+    ctu = new ContentTypeUtil(PATTERN_CACHE, mimeUtil);
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidatorTest.java
index 96168f2..b57ef49 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidatorTest.java
@@ -27,6 +27,7 @@
 import java.util.Map;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -59,30 +60,39 @@
   @Before
   public void setUp() {
     validator =
-        new ContentTypeValidator(null, new ContentTypeUtil(PATTERN_CACHE), null, null, null);
+        new ContentTypeValidator(
+            null,
+            new ContentTypeUtil(PATTERN_CACHE, new FakeMimeUtilFileTypeRegistry()),
+            null,
+            null,
+            null);
   }
 
   @Test
   public void testBlocked() throws Exception {
     String[] patterns = new String[] {"application/pdf", "application/xml", "text/html"};
 
-    List<CommitValidationMessage> m =
-        validator.performValidation(repo, makeCommit(), patterns, false);
-    assertThat(TestUtils.transformMessages(m))
-        .containsExactly(
-            "ERROR: found blocked content type (application/pdf) in file: foo.pdf",
-            "ERROR: found blocked content type (application/xml) in file: foo.xml",
-            "ERROR: found blocked content type (text/html) in file: foo.html");
+    try (RevWalk rw = new RevWalk(repo)) {
+      List<CommitValidationMessage> m =
+          validator.performValidation(repo, makeCommit(rw), rw, patterns, false);
+      assertThat(TestUtils.transformMessages(m))
+          .containsExactly(
+              "ERROR: found blocked content type (application/pdf) in file: foo.pdf",
+              "ERROR: found blocked content type (application/xml) in file: foo.xml",
+              "ERROR: found blocked content type (text/html) in file: foo.html");
+    }
   }
 
   @Test
   public void testWhitelist() throws Exception {
     String[] patterns = new String[] {"application/pdf", "application/xml"};
 
-    List<CommitValidationMessage> m =
-        validator.performValidation(repo, makeCommit(), patterns, true);
-    assertThat(TestUtils.transformMessages(m))
-        .containsExactly("ERROR: found blocked content type (text/html) in file: foo.html");
+    try (RevWalk rw = new RevWalk(repo)) {
+      List<CommitValidationMessage> m =
+          validator.performValidation(repo, makeCommit(rw), rw, patterns, true);
+      assertThat(TestUtils.transformMessages(m))
+          .containsExactly("ERROR: found blocked content type (text/html) in file: foo.html");
+    }
   }
 
   @Test
@@ -91,7 +101,7 @@
     assertThat(ContentTypeValidator.isWhitelist(EMPTY_PLUGIN_CONFIG)).isFalse();
   }
 
-  private RevCommit makeCommit() throws IOException, GitAPIException {
+  private RevCommit makeCommit(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
 
     String content = "<?xml version=\"1.0\"?><a><b>c</b></a>";
@@ -102,6 +112,6 @@
         TestUtils.createEmptyFile("foo.html", repo), content.getBytes(StandardCharsets.UTF_8));
 
     files.put(TestUtils.createEmptyFile("foo.pdf", repo), TEST_PDF);
-    return TestUtils.makeCommit(repo, "Commit with test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with test files.", files);
   }
 }
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidatorTest.java
index cafce5a..4b787b9 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/DuplicatePathnameValidatorTest.java
@@ -36,6 +36,7 @@
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.junit.Before;
 import org.junit.Test;
@@ -57,7 +58,11 @@
       List<CommitValidationMessage> messages,
       List<String> visitedPaths)
       throws Exception {
-    RevCommit c = makeCommit(createEmptyDirCacheEntries(existingTreePaths, testRepo), testRepo);
+    RevCommit c =
+        makeCommit(
+            testRepo.getRevWalk(),
+            createEmptyDirCacheEntries(existingTreePaths, testRepo),
+            testRepo);
     try (TreeWalk tw = new TreeWalk(repo)) {
       tw.setRecursive(false);
       tw.addTree(c.getTree());
@@ -130,41 +135,47 @@
     filenames.add("A");
     filenames.add("F1/ab");
     filenames.add("f2/sF1/aB");
-    RevCommit c = makeCommit(createEmptyDirCacheEntries(filenames, testRepo), testRepo);
-    List<CommitValidationMessage> m = validator.performValidation(repo, c);
-    assertThat(m).hasSize(4);
-    // During checking inside of the commit it's unknown which file is checked
-    // first, because of that, both capabilities must be checked.
-    assertThat(transformMessages(m))
-        .containsAnyOf(transformMessage(conflict("A", "a")), transformMessage(conflict("a", "A")));
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw, createEmptyDirCacheEntries(filenames, testRepo), testRepo);
+      List<CommitValidationMessage> m = validator.performValidation(repo, c, rw);
+      assertThat(m).hasSize(4);
+      // During checking inside of the commit it's unknown which file is checked
+      // first, because of that, both capabilities must be checked.
+      assertThat(transformMessages(m))
+          .containsAnyOf(
+              transformMessage(conflict("A", "a")), transformMessage(conflict("a", "A")));
 
-    assertThat(transformMessages(m))
-        .containsAnyOf(
-            transformMessage(conflict("F1", "f1")), transformMessage(conflict("f1", "F1")));
+      assertThat(transformMessages(m))
+          .containsAnyOf(
+              transformMessage(conflict("F1", "f1")), transformMessage(conflict("f1", "F1")));
 
-    assertThat(transformMessages(m))
-        .containsAnyOf(
-            transformMessage(conflict("F1/ab", "f1/ab")),
-            transformMessage(conflict("f1/ab", "F1/ab")));
+      assertThat(transformMessages(m))
+          .containsAnyOf(
+              transformMessage(conflict("F1/ab", "f1/ab")),
+              transformMessage(conflict("f1/ab", "F1/ab")));
 
-    assertThat(transformMessages(m))
-        .containsAnyOf(
-            transformMessage(conflict("f2/sF1/aB", "f2/sF1/ab")),
-            transformMessage(conflict("f2/sF1/ab", "f2/sF1/aB")));
+      assertThat(transformMessages(m))
+          .containsAnyOf(
+              transformMessage(conflict("f2/sF1/aB", "f2/sF1/ab")),
+              transformMessage(conflict("f2/sF1/ab", "f2/sF1/aB")));
+    }
   }
 
   @Test
   public void testCheckRenaming() throws Exception {
-    RevCommit c = makeCommit(createEmptyDirCacheEntries(INITIAL_PATHNAMES, testRepo), testRepo);
-    DirCacheEntry[] entries = new DirCacheEntry[INITIAL_PATHNAMES.size()];
-    for (int x = 0; x < INITIAL_PATHNAMES.size(); x++) {
-      // Rename files
-      entries[x] =
-          createDirCacheEntry(INITIAL_PATHNAMES.get(x).toUpperCase(), EMPTY_CONTENT, testRepo);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c =
+          makeCommit(rw, createEmptyDirCacheEntries(INITIAL_PATHNAMES, testRepo), testRepo);
+      DirCacheEntry[] entries = new DirCacheEntry[INITIAL_PATHNAMES.size()];
+      for (int x = 0; x < INITIAL_PATHNAMES.size(); x++) {
+        // Rename files
+        entries[x] =
+            createDirCacheEntry(INITIAL_PATHNAMES.get(x).toUpperCase(), EMPTY_CONTENT, testRepo);
+      }
+      RevCommit c1 = makeCommit(rw, entries, testRepo, c);
+      List<CommitValidationMessage> m = validator.performValidation(repo, c1, rw);
+      assertThat(m).isEmpty();
     }
-    RevCommit c1 = makeCommit(entries, testRepo, c);
-    List<CommitValidationMessage> m = validator.performValidation(repo, c1);
-    assertThat(m).isEmpty();
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/EmailAwareValidatorConfigTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/EmailAwareValidatorConfigTest.java
index 09cf4e8..8bdb16c 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/EmailAwareValidatorConfigTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/EmailAwareValidatorConfigTest.java
@@ -35,6 +35,16 @@
   }
 
   @Test
+  public void isEnabledForMissingEmailByDefault() throws Exception {
+    IdentifiedUser missingEmail = new FakeUserProvider().get(null);
+    ValidatorConfig config =
+        getConfig("[plugin \"uploadvalidator\"]\n" + "blockedFileExtension = jar");
+
+    assertThat(config.isEnabledForRef(missingEmail, projectName, "anyRef", "blockedFileExtension"))
+        .isTrue();
+  }
+
+  @Test
   public void isEnabledForSingleEmail() throws Exception {
     ValidatorConfig config =
         getConfig(
@@ -84,6 +94,21 @@
   }
 
   @Test
+  public void missingEmailDoesNotMatchRegex() throws Exception {
+    IdentifiedUser missingEmail = new FakeUserProvider().get(null);
+    ValidatorConfig config =
+        getConfig(
+            "[plugin \"uploadvalidator\"]\n"
+                + "   email = .*$\n"
+                + "   blockedFileExtension = jar");
+
+    assertThat(
+            config.isEnabledForRef(
+                missingEmail, projectName, "refs/heads/anyref", "blockedFileExtension"))
+        .isFalse();
+  }
+
+  @Test
   public void isEnabledForMultipleEmails() throws Exception {
     IdentifiedUser exampleOrgUser = new FakeUserProvider().get("a@example.org");
     IdentifiedUser xUser = new FakeUserProvider().get("x@example.com");
@@ -108,9 +133,7 @@
   }
 
   private ValidatorConfig getConfig(String defaultConfig) throws ConfigInvalidException {
-    ValidatorConfig config =
-        new ValidatorConfig(
-            new FakeConfigFactory(projectName, defaultConfig), new FakeGroupCacheUUIDByName());
-    return config;
+    return new ValidatorConfig(
+        new FakeConfigFactory(projectName, defaultConfig), new FakeGroupByNameFinder());
   }
 }
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupByNameFinder.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupByNameFinder.java
new file mode 100644
index 0000000..69f1b74
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupByNameFinder.java
@@ -0,0 +1,40 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.uploadvalidator;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.reviewdb.client.AccountGroup;
+import com.google.gerrit.server.group.InternalGroup;
+import java.util.Objects;
+import java.util.Optional;
+
+public class FakeGroupByNameFinder implements ValidatorConfig.GroupByNameFinder {
+
+  private final Optional<InternalGroup> onlyGroup;
+
+  public FakeGroupByNameFinder() {
+    onlyGroup = Optional.empty();
+  }
+
+  public FakeGroupByNameFinder(AccountGroup accountGroup) {
+    onlyGroup =
+        Optional.of(InternalGroup.create(accountGroup, ImmutableSet.of(), ImmutableSet.of()));
+  }
+
+  @Override
+  public Optional<InternalGroup> get(AccountGroup.NameKey groupName) {
+    return onlyGroup.filter(group -> Objects.equals(group.getNameKey(), groupName));
+  }
+}
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupCacheUUIDByName.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupCacheUUIDByName.java
deleted file mode 100644
index 02daaf1..0000000
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeGroupCacheUUIDByName.java
+++ /dev/null
@@ -1,64 +0,0 @@
-// Copyright (C) 2017 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.googlesource.gerrit.plugins.uploadvalidator;
-
-import com.google.common.collect.ImmutableList;
-import com.google.gerrit.reviewdb.client.AccountGroup;
-import com.google.gerrit.reviewdb.client.AccountGroup.Id;
-import com.google.gerrit.reviewdb.client.AccountGroup.NameKey;
-import com.google.gerrit.reviewdb.client.AccountGroup.UUID;
-import com.google.gerrit.server.account.GroupCache;
-import java.io.IOException;
-
-public class FakeGroupCacheUUIDByName implements GroupCache {
-  private AccountGroup accountGroup;
-
-  public FakeGroupCacheUUIDByName(AccountGroup accountGroup) {
-    this.accountGroup = accountGroup;
-  }
-
-  public FakeGroupCacheUUIDByName() {
-    // TODO Auto-generated constructor stub
-  }
-
-  @Override
-  public AccountGroup get(Id groupId) {
-    return null;
-  }
-
-  @Override
-  public AccountGroup get(NameKey name) {
-    return accountGroup != null && accountGroup.getNameKey().equals(name) ? accountGroup : null;
-  }
-
-  @Override
-  public AccountGroup get(UUID uuid) {
-    return null;
-  }
-
-  @Override
-  public ImmutableList<AccountGroup> all() {
-    return null;
-  }
-
-  @Override
-  public void onCreateGroup(NameKey newGroupName) throws IOException {}
-
-  @Override
-  public void evict(AccountGroup group) throws IOException {}
-
-  @Override
-  public void evictAfterRename(NameKey oldName, NameKey newName) throws IOException {}
-}
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeMimeUtilFileTypeRegistry.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeMimeUtilFileTypeRegistry.java
new file mode 100644
index 0000000..d1d50bc
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FakeMimeUtilFileTypeRegistry.java
@@ -0,0 +1,57 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.uploadvalidator;
+
+import com.google.gerrit.server.mime.FileTypeRegistry;
+import com.google.inject.Singleton;
+import eu.medsea.mimeutil.MimeType;
+import java.io.InputStream;
+
+@Singleton
+class FakeMimeUtilFileTypeRegistry implements FileTypeRegistry {
+
+  @Override
+  public MimeType getMimeType(String path, byte[] content) {
+    if (path.endsWith(".pdf")) {
+      return new MimeType("application/pdf");
+    }
+    if (path.endsWith(".xml")) {
+      return new MimeType("application/xml");
+    }
+    if (path.endsWith(".html")) {
+      return new MimeType("text/html");
+    }
+    return new MimeType("application/octet-stream");
+  }
+
+  @Override
+  public MimeType getMimeType(String path, InputStream is) {
+    if (path.endsWith(".pdf")) {
+      return new MimeType("application/pdf");
+    }
+    if (path.endsWith(".xml")) {
+      return new MimeType("application/xml");
+    }
+    if (path.endsWith(".html")) {
+      return new MimeType("text/html");
+    }
+    return new MimeType("application/octet-stream");
+  }
+
+  @Override
+  public boolean isSafeInline(MimeType type) {
+    return false;
+  }
+}
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidatorTest.java
index ed09b61..65bc8fb 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/FileExtensionValidatorTest.java
@@ -28,6 +28,7 @@
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.api.errors.NoFilepatternException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class FileExtensionValidatorTest extends ValidatorTestCase {
@@ -36,7 +37,7 @@
   private static final List<String> BLOCKED_EXTENSIONS_UC =
       Lists.newArrayList("JPEG", "PDF", "ZIP", "EXE", "TAR.GZ");
 
-  private RevCommit makeCommit(List<String> blockedExtensions)
+  private RevCommit makeCommit(RevWalk rw, List<String> blockedExtensions)
       throws NoFilepatternException, IOException, GitAPIException {
     Set<File> files = new HashSet<>();
     for (String extension : blockedExtensions) {
@@ -47,31 +48,35 @@
     files.add(new File(repo.getDirectory().getParent(), "foo.core.tmp"));
     files.add(new File(repo.getDirectory().getParent(), "foo.c"));
     files.add(new File(repo.getDirectory().getParent(), "foo.txt"));
-    return TestUtils.makeCommit(repo, "Commit with empty test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with empty test files.", files);
   }
 
   @Test
   public void testBlockedExtensions() throws Exception {
-    RevCommit c = makeCommit(BLOCKED_EXTENSIONS_LC);
-    List<CommitValidationMessage> m =
-        FileExtensionValidator.performValidation(repo, c, BLOCKED_EXTENSIONS_LC);
-    List<String> expected = new ArrayList<>();
-    for (String extension : BLOCKED_EXTENSIONS_LC) {
-      expected.add("ERROR: blocked file: foo." + extension);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw, BLOCKED_EXTENSIONS_LC);
+      List<CommitValidationMessage> m =
+          FileExtensionValidator.performValidation(repo, c, rw, BLOCKED_EXTENSIONS_LC);
+      List<String> expected = new ArrayList<>();
+      for (String extension : BLOCKED_EXTENSIONS_LC) {
+        expected.add("ERROR: blocked file: foo." + extension);
+      }
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
     }
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
   }
 
   @Test
   public void testBlockedExtensionsCaseInsensitive() throws Exception {
-    RevCommit c = makeCommit(BLOCKED_EXTENSIONS_UC);
-    List<CommitValidationMessage> m =
-        FileExtensionValidator.performValidation(repo, c, BLOCKED_EXTENSIONS_LC);
-    List<String> expected = new ArrayList<>();
-    for (String extension : BLOCKED_EXTENSIONS_UC) {
-      expected.add("ERROR: blocked file: foo." + extension);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw, BLOCKED_EXTENSIONS_UC);
+      List<CommitValidationMessage> m =
+          FileExtensionValidator.performValidation(repo, c, rw, BLOCKED_EXTENSIONS_LC);
+      List<String> expected = new ArrayList<>();
+      for (String extension : BLOCKED_EXTENSIONS_UC) {
+        expected.add("ERROR: blocked file: foo." + extension);
+      }
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
     }
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidatorTest.java
index 45003b7..a84ad32 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidFilenameValidatorTest.java
@@ -25,6 +25,7 @@
 import java.util.Set;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class InvalidFilenameValidatorTest extends ValidatorTestCase {
@@ -40,27 +41,29 @@
     return filenames;
   }
 
-  private RevCommit makeCommit() throws IOException, GitAPIException {
+  private RevCommit makeCommit(RevWalk rw) throws IOException, GitAPIException {
     Set<File> files = new HashSet<>();
     for (String filenames : getInvalidFilenames()) {
       files.add(new File(repo.getDirectory().getParent(), filenames));
     }
     // valid filename
     files.add(new File(repo.getDirectory().getParent(), "test"));
-    return TestUtils.makeCommit(repo, "Commit with empty test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with empty test files.", files);
   }
 
   @Test
   public void test() throws Exception {
     String[] invalidFilenamePattern = {"\\[|\\]|\\*|#", "[%:@]"};
-    RevCommit c = makeCommit();
-    List<CommitValidationMessage> m =
-        InvalidFilenameValidator.performValidation(repo, c, invalidFilenamePattern);
-    Set<String> expected = new HashSet<>();
-    for (String filenames : getInvalidFilenames()) {
-      expected.add("ERROR: invalid characters found in filename: " + filenames);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw);
+      List<CommitValidationMessage> m =
+          InvalidFilenameValidator.performValidation(repo, c, rw, invalidFilenamePattern);
+      Set<String> expected = new HashSet<>();
+      for (String filenames : getInvalidFilenames()) {
+        expected.add("ERROR: invalid characters found in filename: " + filenames);
+      }
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
     }
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidatorTest.java
index 9b35e7a..17209d2 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidatorTest.java
@@ -27,10 +27,11 @@
 import java.util.Map;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class InvalidLineEndingValidatorTest extends ValidatorTestCase {
-  private RevCommit makeCommit() throws IOException, GitAPIException {
+  private RevCommit makeCommit(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
     // invalid line endings
     String content = "Testline1\r\n" + "Testline2\n" + "Testline3\r\n" + "Testline4";
@@ -43,17 +44,25 @@
     files.put(
         new File(repo.getDirectory().getParent(), "bar.txt"),
         content.getBytes(StandardCharsets.UTF_8));
-    return TestUtils.makeCommit(repo, "Commit with test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with test files.", files);
   }
 
   @Test
   public void testCarriageReturn() throws Exception {
-    RevCommit c = makeCommit();
-    InvalidLineEndingValidator validator =
-        new InvalidLineEndingValidator(null, new ContentTypeUtil(PATTERN_CACHE), null, null, null);
-    List<CommitValidationMessage> m = validator.performValidation(repo, c, EMPTY_PLUGIN_CONFIG);
-    assertThat(TestUtils.transformMessages(m))
-        .containsExactly("ERROR: found carriage return (CR) character in file: foo.txt");
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw);
+      InvalidLineEndingValidator validator =
+          new InvalidLineEndingValidator(
+              null,
+              new ContentTypeUtil(PATTERN_CACHE, new FakeMimeUtilFileTypeRegistry()),
+              null,
+              null,
+              null);
+      List<CommitValidationMessage> m =
+          validator.performValidation(repo, c, rw, EMPTY_PLUGIN_CONFIG);
+      assertThat(TestUtils.transformMessages(m))
+          .containsExactly("ERROR: found carriage return (CR) character in file: foo.txt");
+    }
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidatorTest.java
index 27289be..f4578c9 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/MaxPathLengthValidatorTest.java
@@ -27,6 +27,7 @@
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class MaxPathLengthValidatorTest extends ValidatorTestCase {
@@ -37,34 +38,39 @@
     return (TOO_LONG.length() + GOOD.length()) / 2;
   }
 
-  private RevCommit makeCommit() throws IOException, GitAPIException {
+  private RevCommit makeCommit(RevWalk rw) throws IOException, GitAPIException {
     Set<File> files = new HashSet<>();
     files.add(TestUtils.createEmptyFile(TOO_LONG, repo));
     files.add(TestUtils.createEmptyFile(GOOD, repo));
-    return TestUtils.makeCommit(repo, "Commit with empty test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with empty test files.", files);
   }
 
   @Test
   public void testAddTooLongPath() throws Exception {
-    RevCommit c = makeCommit();
-    List<CommitValidationMessage> m =
-        MaxPathLengthValidator.performValidation(repo, c, getMaxPathLength());
-    Set<String> expected = ImmutableSet.of("ERROR: path too long: " + TOO_LONG);
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw);
+      List<CommitValidationMessage> m =
+          MaxPathLengthValidator.performValidation(repo, c, rw, getMaxPathLength());
+      Set<String> expected = ImmutableSet.of("ERROR: path too long: " + TOO_LONG);
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    }
   }
 
   @Test
   public void testDeleteTooLongPath() throws Exception {
-    RevCommit c = makeCommit();
-    try (Git git = new Git(repo)) {
-      Set<File> files = new HashSet<>();
-      files.add(TestUtils.createEmptyFile(TOO_LONG, repo));
-      TestUtils.removeFiles(git, files);
-      c = git.commit().setMessage("Delete file which is too long").call();
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommit(rw);
+      try (Git git = new Git(repo)) {
+        Set<File> files = new HashSet<>();
+        files.add(TestUtils.createEmptyFile(TOO_LONG, repo));
+        TestUtils.removeFiles(git, files);
+        c = git.commit().setMessage("Delete file which is too long").call();
+        rw.parseCommit(c);
+      }
+      List<CommitValidationMessage> m =
+          MaxPathLengthValidator.performValidation(repo, c, rw, getMaxPathLength());
+      assertThat(m).isEmpty();
     }
-    List<CommitValidationMessage> m =
-        MaxPathLengthValidator.performValidation(repo, c, getMaxPathLength());
-    assertThat(m).isEmpty();
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ProjectAwareValidatorConfigTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ProjectAwareValidatorConfigTest.java
index 9949778..e6e1be7 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ProjectAwareValidatorConfigTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/ProjectAwareValidatorConfigTest.java
@@ -99,9 +99,7 @@
 
   private ValidatorConfig getConfig(String defaultConfig, Project.NameKey projName)
       throws ConfigInvalidException {
-    ValidatorConfig config =
-        new ValidatorConfig(
-            new FakeConfigFactory(projName, defaultConfig), new FakeGroupCacheUUIDByName());
-    return config;
+    return new ValidatorConfig(
+        new FakeConfigFactory(projName, defaultConfig), new FakeGroupByNameFinder());
   }
 }
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/RefAwareValidatorConfigTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/RefAwareValidatorConfigTest.java
index fc9b486..acc2bdc 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/RefAwareValidatorConfigTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/RefAwareValidatorConfigTest.java
@@ -104,9 +104,7 @@
   }
 
   private ValidatorConfig getConfig(String defaultConfig) throws ConfigInvalidException {
-    ValidatorConfig config =
-        new ValidatorConfig(
-            new FakeConfigFactory(projectName, defaultConfig), new FakeGroupCacheUUIDByName());
-    return config;
+    return new ValidatorConfig(
+        new FakeConfigFactory(projectName, defaultConfig), new FakeGroupByNameFinder());
   }
 }
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SkipValidationTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SkipValidationTest.java
index 2b0f5cd..4942391 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SkipValidationTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SkipValidationTest.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.gerrit.common.TimeUtil;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.IdentifiedUser;
@@ -28,7 +29,7 @@
   @Test
   public void dontSkipByDefault() throws Exception {
     ValidatorConfig validatorConfig =
-        new ValidatorConfig(new FakeConfigFactory(projectName, ""), new FakeGroupCacheUUIDByName());
+        new ValidatorConfig(new FakeConfigFactory(projectName, ""), new FakeGroupByNameFinder());
 
     assertThat(validatorConfig.isEnabledForRef(anyUser, projectName, "anyRef", "anyOp")).isTrue();
   }
@@ -43,7 +44,7 @@
 
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
-            new FakeConfigFactory(projectName, config), new FakeGroupCacheUUIDByName());
+            new FakeConfigFactory(projectName, config), new FakeGroupByNameFinder());
 
     assertThat(
             validatorConfig.isEnabledForRef(
@@ -62,11 +63,12 @@
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
             new FakeConfigFactory(projectName, config),
-            new FakeGroupCacheUUIDByName(
+            new FakeGroupByNameFinder(
                 new AccountGroup(
                     new AccountGroup.NameKey("testGroupName"),
                     new AccountGroup.Id(1),
-                    new AccountGroup.UUID("testGroupId"))));
+                    new AccountGroup.UUID("testGroupId"),
+                    TimeUtil.nowTs())));
 
     assertThat(
             validatorConfig.isEnabledForRef(
@@ -84,7 +86,7 @@
 
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
-            new FakeConfigFactory(projectName, config), new FakeGroupCacheUUIDByName());
+            new FakeConfigFactory(projectName, config), new FakeGroupByNameFinder());
 
     assertThat(
             validatorConfig.isEnabledForRef(
@@ -102,7 +104,7 @@
 
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
-            new FakeConfigFactory(projectName, config), new FakeGroupCacheUUIDByName());
+            new FakeConfigFactory(projectName, config), new FakeGroupByNameFinder());
 
     assertThat(validatorConfig.isEnabledForRef(anyUser, projectName, "anyRef", "anotherOp"))
         .isTrue();
@@ -118,7 +120,7 @@
 
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
-            new FakeConfigFactory(projectName, config), new FakeGroupCacheUUIDByName());
+            new FakeConfigFactory(projectName, config), new FakeGroupByNameFinder());
 
     assertThat(
             validatorConfig.isEnabledForRef(
@@ -136,7 +138,7 @@
 
     ValidatorConfig validatorConfig =
         new ValidatorConfig(
-            new FakeConfigFactory(projectName, config), new FakeGroupCacheUUIDByName());
+            new FakeConfigFactory(projectName, config), new FakeGroupByNameFinder());
 
     assertThat(
             validatorConfig.isEnabledForRef(
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidatorTest.java
index 11c1651..a21d46f 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SubmoduleValidatorTest.java
@@ -27,39 +27,44 @@
 import org.eclipse.jgit.api.SubmoduleAddCommand;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class SubmoduleValidatorTest extends ValidatorTestCase {
-  private RevCommit makeCommitWithSubmodule() throws IOException, GitAPIException {
+  private RevCommit makeCommitWithSubmodule(RevWalk rw) throws IOException, GitAPIException {
     try (Git git = new Git(repo)) {
       SubmoduleAddCommand addCommand = git.submoduleAdd();
       addCommand.setURI(repo.getDirectory().getCanonicalPath());
       addCommand.setPath("modules/library");
       addCommand.call().close();
       git.add().addFilepattern(".").call();
-      return git.commit().setMessage("Commit with submodule.").call();
+      return rw.parseCommit(git.commit().setMessage("Commit with submodule.").call());
     }
   }
 
   @Test
   public void testWithSubmodule() throws Exception {
-    RevCommit c = makeCommitWithSubmodule();
-    List<CommitValidationMessage> m = SubmoduleValidator.performValidation(repo, c);
-    assertThat(TestUtils.transformMessages(m))
-        .containsExactly("ERROR: submodules are not allowed: modules/library");
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommitWithSubmodule(rw);
+      List<CommitValidationMessage> m = SubmoduleValidator.performValidation(repo, c, rw);
+      assertThat(TestUtils.transformMessages(m))
+          .containsExactly("ERROR: submodules are not allowed: modules/library");
+    }
   }
 
-  private RevCommit makeCommitWithoutSubmodule() throws IOException, GitAPIException {
+  private RevCommit makeCommitWithoutSubmodule(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
     files.put(new File(repo.getDirectory().getParent(), "foo.txt"), null);
-    return TestUtils.makeCommit(repo, "Commit with empty test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with empty test files.", files);
   }
 
   @Test
   public void testWithoutSubmodule() throws Exception {
-    RevCommit c = makeCommitWithoutSubmodule();
-    List<CommitValidationMessage> m = SubmoduleValidator.performValidation(repo, c);
-    assertThat(m).isEmpty();
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommitWithoutSubmodule(rw);
+      List<CommitValidationMessage> m = SubmoduleValidator.performValidation(repo, c, rw);
+      assertThat(m).isEmpty();
+    }
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidatorTest.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidatorTest.java
index fde0b4b..1432c42 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidatorTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/SymlinkValidatorTest.java
@@ -29,10 +29,11 @@
 import java.util.Set;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 public class SymlinkValidatorTest extends ValidatorTestCase {
-  private RevCommit makeCommitWithSymlink() throws IOException, GitAPIException {
+  private RevCommit makeCommitWithSymlink(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
     File link = new File(repo.getDirectory().getParent(), "foo.txt");
     Files.createSymbolicLink(link.toPath(), Paths.get("bar.txt"));
@@ -42,31 +43,37 @@
     Files.createSymbolicLink(link.toPath(), Paths.get("folder"));
     files.put(link, null);
 
-    return TestUtils.makeCommit(repo, "Commit with symlink.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with symlink.", files);
   }
 
   @Test
   public void testWithSymlink() throws Exception {
-    RevCommit c = makeCommitWithSymlink();
-    List<CommitValidationMessage> m = SymlinkValidator.performValidation(repo, c);
-    Set<String> expected =
-        ImmutableSet.of(
-            "ERROR: Symbolic links are not allowed: foo.txt",
-            "ERROR: Symbolic links are not allowed: symbolicFolder");
-    assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommitWithSymlink(rw);
+      List<CommitValidationMessage> m =
+          SymlinkValidator.performValidation(repo, rw.parseCommit(c), rw);
+      Set<String> expected =
+          ImmutableSet.of(
+              "ERROR: Symbolic links are not allowed: foo.txt",
+              "ERROR: Symbolic links are not allowed: symbolicFolder");
+      assertThat(TestUtils.transformMessages(m)).containsExactlyElementsIn(expected);
+    }
   }
 
-  private RevCommit makeCommitWithoutSymlink() throws IOException, GitAPIException {
+  private RevCommit makeCommitWithoutSymlink(RevWalk rw) throws IOException, GitAPIException {
     Map<File, byte[]> files = new HashMap<>();
     files.put(new File(repo.getDirectory().getParent(), "foo.txt"), null);
-    return TestUtils.makeCommit(repo, "Commit with empty test files.", files);
+    return TestUtils.makeCommit(rw, repo, "Commit with empty test files.", files);
   }
 
   @Test
   public void testWithoutSymlink() throws Exception {
-    RevCommit c = makeCommitWithoutSymlink();
-    List<CommitValidationMessage> m = SymlinkValidator.performValidation(repo, c);
-    assertThat(m).isEmpty();
+    try (RevWalk rw = new RevWalk(repo)) {
+      RevCommit c = makeCommitWithoutSymlink(rw);
+      List<CommitValidationMessage> m =
+          SymlinkValidator.performValidation(repo, rw.parseCommit(c), rw);
+      assertThat(m).isEmpty();
+    }
   }
 
   @Test
diff --git a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/TestUtils.java b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/TestUtils.java
index a3b9089..22f95f0 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/TestUtils.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/uploadvalidator/TestUtils.java
@@ -39,6 +39,7 @@
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
 
 public class TestUtils {
@@ -64,22 +65,23 @@
     return repository;
   }
 
-  public static RevCommit makeCommit(Repository repo, String message, Set<File> files)
+  public static RevCommit makeCommit(RevWalk rw, Repository repo, String message, Set<File> files)
       throws IOException, GitAPIException {
     Map<File, byte[]> tmp = new HashMap<>();
     for (File f : files) {
       tmp.put(f, null);
     }
-    return makeCommit(repo, message, tmp);
+    return makeCommit(rw, repo, message, tmp);
   }
 
-  public static RevCommit makeCommit(Repository repo, String message, Map<File, byte[]> files)
+  public static RevCommit makeCommit(
+      RevWalk rw, Repository repo, String message, Map<File, byte[]> files)
       throws IOException, GitAPIException {
     try (Git git = new Git(repo)) {
       if (files != null) {
         addFiles(git, files);
       }
-      return git.commit().setMessage(message).call();
+      return rw.parseCommit(git.commit().setMessage(message).call());
     }
   }
 
@@ -138,17 +140,17 @@
     return repo.file(pathname, repo.blob(content));
   }
 
-  public static RevCommit makeCommit(DirCacheEntry[] entries, TestRepository<Repository> repo)
-      throws Exception {
-    return makeCommit(entries, repo, (RevCommit[]) null);
+  public static RevCommit makeCommit(
+      RevWalk rw, DirCacheEntry[] entries, TestRepository<Repository> repo) throws Exception {
+    return makeCommit(rw, entries, repo, (RevCommit[]) null);
   }
 
   public static RevCommit makeCommit(
-      DirCacheEntry[] entries, TestRepository<Repository> repo, RevCommit... parents)
+      RevWalk rw, DirCacheEntry[] entries, TestRepository<Repository> repo, RevCommit... parents)
       throws Exception {
     final RevTree ta = repo.tree(entries);
     RevCommit c = (parents == null) ? repo.commit(ta) : repo.commit(ta, parents);
     repo.parseBody(c);
-    return c;
+    return rw.parseCommit(c);
   }
 }