diff --git a/java/com/google/gerrit/entities/EmailHeader.java b/java/com/google/gerrit/entities/EmailHeader.java
index bf5a644..1ad626d 100644
--- a/java/com/google/gerrit/entities/EmailHeader.java
+++ b/java/com/google/gerrit/entities/EmailHeader.java
@@ -157,7 +157,7 @@
 
     @Override
     public boolean equals(Object o) {
-      return (o instanceof Date) && Objects.equals(value, ((Date) o).value);
+      return (o instanceof Date) && Objects.equals(value.getTime(), ((Date) o).value.getTime());
     }
 
     @Override
diff --git a/java/com/google/gerrit/extensions/common/ChangeMessageInfo.java b/java/com/google/gerrit/extensions/common/ChangeMessageInfo.java
index c1cb1627..e7e46c1 100644
--- a/java/com/google/gerrit/extensions/common/ChangeMessageInfo.java
+++ b/java/com/google/gerrit/extensions/common/ChangeMessageInfo.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.extensions.common;
 
+import com.google.common.collect.Iterables;
 import java.sql.Timestamp;
 import java.util.Collection;
 import java.util.Objects;
@@ -45,7 +46,10 @@
           && Objects.equals(realAuthor, cmi.realAuthor)
           && Objects.equals(date, cmi.date)
           && Objects.equals(message, cmi.message)
-          && Objects.equals(accountsInMessage, cmi.accountsInMessage)
+          && ((accountsInMessage == null && cmi.accountsInMessage == null)
+              || (accountsInMessage != null
+                  && cmi.accountsInMessage != null
+                  && Iterables.elementsEqual(accountsInMessage, cmi.accountsInMessage)))
           && Objects.equals(_revisionNumber, cmi._revisionNumber);
     }
     return false;
diff --git a/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java b/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
index d827d5d..0f6af21 100644
--- a/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
@@ -24,7 +24,6 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.common.GitPerson;
 import java.sql.Timestamp;
-import java.util.Date;
 import org.eclipse.jgit.lib.PersonIdent;
 
 public class GitPersonSubject extends Subject {
@@ -75,7 +74,7 @@
     isNotNull();
     name().isEqualTo(ident.getName());
     email().isEqualTo(ident.getEmailAddress());
-    check("roundedDate()").that(new Date(gitPerson.date.getTime())).isEqualTo(ident.getWhen());
+    check("roundedDate()").that(gitPerson.date.getTime()).isEqualTo(ident.getWhen().getTime());
     tz().isEqualTo(ident.getTimeZoneOffset());
   }
 }
diff --git a/java/com/google/gerrit/testing/TestCommentHelper.java b/java/com/google/gerrit/testing/TestCommentHelper.java
index 5865a3c..400b559 100644
--- a/java/com/google/gerrit/testing/TestCommentHelper.java
+++ b/java/com/google/gerrit/testing/TestCommentHelper.java
@@ -33,6 +33,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 
 /** Test helper for dealing with comments/drafts. */
 public class TestCommentHelper {
@@ -64,7 +65,7 @@
     gApi.changes().id(changeId).current().createDraft(in);
   }
 
-  public Collection<CommentInfo> getPublishedComments(String changeId) throws Exception {
+  public List<CommentInfo> getPublishedComments(String changeId) throws Exception {
     return gApi.changes().id(changeId).commentsRequest().get().values().stream()
         .flatMap(Collection::stream)
         .collect(toList());
diff --git a/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java b/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
index 194f5f9..ef9f004 100644
--- a/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
@@ -1397,12 +1397,13 @@
     String patchSetRef = change.getPatchSetId().toRefName();
     try (AutoCloseable ignored = disableChangeIndex();
         Repository repo = repoManager.openRepository(project)) {
-      Collection<Ref> singleRef = ImmutableList.of(repo.exactRef(patchSetRef));
-      Collection<Ref> filteredRefs =
-          permissionBackend
-              .user(user(admin))
-              .project(project)
-              .filter(singleRef, repo, RefFilterOptions.defaults());
+      ImmutableList<Ref> singleRef = ImmutableList.of(repo.exactRef(patchSetRef));
+      ImmutableList<Ref> filteredRefs =
+          ImmutableList.copyOf(
+              permissionBackend
+                  .user(user(admin))
+                  .project(project)
+                  .filter(singleRef, repo, RefFilterOptions.defaults()));
       assertThat(filteredRefs).isEqualTo(singleRef);
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
index 317053e..b55561b 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
@@ -1361,7 +1361,8 @@
   }
 
   protected void assertAuthorAndCommitDateEquals(RevCommit commit) {
-    assertThat(commit.getAuthorIdent().getWhen()).isEqualTo(commit.getCommitterIdent().getWhen());
+    assertThat(commit.getAuthorIdent().getWhen().getTime())
+        .isEqualTo(commit.getCommitterIdent().getWhen().getTime());
     assertThat(commit.getAuthorIdent().getTimeZone())
         .isEqualTo(commit.getCommitterIdent().getTimeZone());
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/ChangeReviewersByEmailIT.java b/javatests/com/google/gerrit/acceptance/rest/change/ChangeReviewersByEmailIT.java
index 88e5f10..dc25046 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/ChangeReviewersByEmailIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/ChangeReviewersByEmailIT.java
@@ -65,9 +65,9 @@
       gApi.changes().id(r.getChangeId()).addReviewer(input);
 
       ChangeInfo info = gApi.changes().id(r.getChangeId()).get(DETAILED_LABELS);
-      assertThat(info.reviewers).isEqualTo(ImmutableMap.of(state, ImmutableList.of(acc)));
+      assertThat(info.reviewers).containsExactly(state, ImmutableList.of(acc));
       // All reviewers added by email should be removable
-      assertThat(info.removableReviewers).isEqualTo(ImmutableList.of(acc));
+      assertThat(info.removableReviewers).containsExactly(acc);
     }
   }
 
@@ -92,7 +92,7 @@
       ChangeInfo info = gApi.changes().id(r.getChangeId()).get(DETAILED_LABELS);
       assertThat(info.reviewers).isEqualTo(ImmutableMap.of(state, ImmutableList.of(byId, byEmail)));
       // All reviewers (both by id and by email) should be removable
-      assertThat(info.removableReviewers).isEqualTo(ImmutableList.of(byId, byEmail));
+      assertThat(info.removableReviewers).containsExactly(byId, byEmail);
     }
   }
 
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
index d4000b3..bd51506 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
@@ -436,7 +436,7 @@
     String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", COMMENT_TEXT, null, null);
     b.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
-    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    List<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
     mailProcessor.process(b.build());
     assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
 
@@ -465,7 +465,7 @@
     String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", null, COMMENT_TEXT, null);
     b.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
-    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    List<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
     mailProcessor.process(b.build());
     assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
 
@@ -490,7 +490,7 @@
     String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", null, null, COMMENT_TEXT);
     b.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
-    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    List<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
     mailProcessor.process(b.build());
     assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
 
@@ -576,7 +576,7 @@
             null);
     mailMessage.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
-    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    List<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
     mailProcessor.process(mailMessage.build());
     assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
 
diff --git a/javatests/com/google/gerrit/common/BUILD b/javatests/com/google/gerrit/common/BUILD
index c7b21a3..492d007 100644
--- a/javatests/com/google/gerrit/common/BUILD
+++ b/javatests/com/google/gerrit/common/BUILD
@@ -11,6 +11,7 @@
         "//lib:guava",
         "//lib/auto:auto-value",
         "//lib/auto:auto-value-annotations",
+        "//lib/log:log4j",
         "//lib/truth",
     ],
 )
diff --git a/javatests/com/google/gerrit/server/group/db/GroupConfigTest.java b/javatests/com/google/gerrit/server/group/db/GroupConfigTest.java
index 5d88a5f..31b2bc3 100644
--- a/javatests/com/google/gerrit/server/group/db/GroupConfigTest.java
+++ b/javatests/com/google/gerrit/server/group/db/GroupConfigTest.java
@@ -1068,7 +1068,7 @@
     }
 
     RevCommit revCommit = getLatestCommitForGroup(groupUuid);
-    assertThat(revCommit.getCommitterIdent().getWhen()).isEqualTo(createdOn);
+    assertThat(revCommit.getCommitterIdent().getWhen().getTime()).isEqualTo(createdOn.getTime());
     assertThat(revCommit.getCommitterIdent().getTimeZone().getRawOffset())
         .isEqualTo(timeZone.getRawOffset());
   }
@@ -1101,7 +1101,7 @@
     }
 
     RevCommit revCommit = getLatestCommitForGroup(groupUuid);
-    assertThat(revCommit.getAuthorIdent().getWhen()).isEqualTo(createdOn);
+    assertThat(revCommit.getAuthorIdent().getWhen().getTime()).isEqualTo(createdOn.getTime());
     assertThat(revCommit.getAuthorIdent().getTimeZone().getRawOffset())
         .isEqualTo(timeZone.getRawOffset());
   }
@@ -1160,7 +1160,7 @@
     }
 
     RevCommit revCommit = getLatestCommitForGroup(groupUuid);
-    assertThat(revCommit.getCommitterIdent().getWhen()).isEqualTo(updatedOn);
+    assertThat(revCommit.getCommitterIdent().getWhen().getTime()).isEqualTo(updatedOn.getTime());
     assertThat(revCommit.getCommitterIdent().getTimeZone().getRawOffset())
         .isEqualTo(timeZone.getRawOffset());
   }
@@ -1188,7 +1188,7 @@
     }
 
     RevCommit revCommit = getLatestCommitForGroup(groupUuid);
-    assertThat(revCommit.getAuthorIdent().getWhen()).isEqualTo(updatedOn);
+    assertThat(revCommit.getAuthorIdent().getWhen().getTime()).isEqualTo(updatedOn.getTime());
     assertThat(revCommit.getAuthorIdent().getTimeZone().getRawOffset())
         .isEqualTo(timeZone.getRawOffset());
   }
diff --git a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
index 6ce8f7c..ce4ec39 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
@@ -27,7 +27,6 @@
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.util.time.TimeUtil;
 import com.google.gerrit.testing.TestChanges;
-import java.util.Date;
 import java.util.TimeZone;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -68,13 +67,13 @@
     PersonIdent author = commit.getAuthorIdent();
     assertThat(author.getName()).isEqualTo("Gerrit User 1");
     assertThat(author.getEmailAddress()).isEqualTo("1@gerrit");
-    assertThat(author.getWhen()).isEqualTo(new Date(c.getCreatedOn().getTime() + 1000));
+    assertThat(author.getWhen().getTime()).isEqualTo(c.getCreatedOn().getTime() + 1000);
     assertThat(author.getTimeZone()).isEqualTo(TimeZone.getTimeZone("GMT-7:00"));
 
     PersonIdent committer = commit.getCommitterIdent();
     assertThat(committer.getName()).isEqualTo("Gerrit Server");
     assertThat(committer.getEmailAddress()).isEqualTo("noreply@gerrit.com");
-    assertThat(committer.getWhen()).isEqualTo(author.getWhen());
+    assertThat(committer.getWhen().getTime()).isEqualTo(author.getWhen().getTime());
     assertThat(committer.getTimeZone()).isEqualTo(author.getTimeZone());
   }
 
@@ -184,13 +183,13 @@
     PersonIdent author = commit.getAuthorIdent();
     assertThat(author.getName()).isEqualTo("Gerrit User 1");
     assertThat(author.getEmailAddress()).isEqualTo("1@gerrit");
-    assertThat(author.getWhen()).isEqualTo(new Date(c.getCreatedOn().getTime() + 2000));
+    assertThat(author.getWhen().getTime()).isEqualTo(c.getCreatedOn().getTime() + 2000);
     assertThat(author.getTimeZone()).isEqualTo(TimeZone.getTimeZone("GMT-7:00"));
 
     PersonIdent committer = commit.getCommitterIdent();
     assertThat(committer.getName()).isEqualTo("Gerrit Server");
     assertThat(committer.getEmailAddress()).isEqualTo("noreply@gerrit.com");
-    assertThat(committer.getWhen()).isEqualTo(author.getWhen());
+    assertThat(committer.getWhen().getTime()).isEqualTo(author.getWhen().getTime());
     assertThat(committer.getTimeZone()).isEqualTo(author.getTimeZone());
   }
 
diff --git a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
index bc2d095..b29ce29 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
@@ -370,7 +370,8 @@
     assertThat(fixedUpdateCommit.getAuthorIdent().getName())
         .isEqualTo("Gerrit User " + changeOwner.getAccountId());
     assertThat(originalAuthorIdent.getEmailAddress()).isEqualTo(fixedAuthorIdent.getEmailAddress());
-    assertThat(originalAuthorIdent.getWhen()).isEqualTo(fixedAuthorIdent.getWhen());
+    assertThat(originalAuthorIdent.getWhen().getTime())
+        .isEqualTo(fixedAuthorIdent.getWhen().getTime());
     assertThat(originalAuthorIdent.getTimeZone()).isEqualTo(fixedAuthorIdent.getTimeZone());
     assertThat(invalidUpdateCommit.getFullMessage()).isEqualTo(fixedUpdateCommit.getFullMessage());
     assertThat(invalidUpdateCommit.getCommitterIdent())
diff --git a/tools/BUILD b/tools/BUILD
index 6252312..c5da873 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -430,7 +430,7 @@
         "-Xep:TypeParameterShadowing:ERROR",
         "-Xep:TypeParameterUnusedInFormals:ERROR",
         "-Xep:URLEqualsHashCode:ERROR",
-        # "-Xep:UndefinedEquals:WARN",
+        "-Xep:UndefinedEquals:ERROR",
         "-Xep:UnescapedEntity:ERROR",
         "-Xep:UnnecessaryAssignment:ERROR",
         "-Xep:UnnecessaryCheckNotNull:ERROR",
diff --git a/tools/nongoogle.bzl b/tools/nongoogle.bzl
index 51be39f..0cb3870 100644
--- a/tools/nongoogle.bzl
+++ b/tools/nongoogle.bzl
@@ -123,24 +123,24 @@
     # Google internal dependencies: these are developed at Google, so there is
     # no concern about version skew.
 
-    FLOGGER_VERS = "0.6"
+    FLOGGER_VERS = "0.7.3"
 
     maven_jar(
         name = "flogger",
         artifact = "com.google.flogger:flogger:" + FLOGGER_VERS,
-        sha1 = "155dc6e303a58f7bbff5d2cd1a259de86827f4fe",
+        sha1 = "d08bf8276d2bbb1435951e88b3f067092285b9fb",
     )
 
     maven_jar(
         name = "flogger-log4j-backend",
         artifact = "com.google.flogger:flogger-log4j-backend:" + FLOGGER_VERS,
-        sha1 = "9743841bf10309163effd8ddf882b5d5190cc9d9",
+        sha1 = "7486b1c0138647cd7714eccb8ce37b5f2ae20a76",
     )
 
     maven_jar(
         name = "flogger-system-backend",
         artifact = "com.google.flogger:flogger-system-backend:" + FLOGGER_VERS,
-        sha1 = "0f0ccf8923c6c315f2f57b108bcc6e46ccd88777",
+        sha1 = "4bee7ebbd97c63ca7fb17529aeb49a57b670d061",
     )
 
     maven_jar(