diff --git a/java/com/google/gerrit/server/change/IncludedInRefs.java b/java/com/google/gerrit/server/change/IncludedInRefs.java
index 63340dc..17a0c9d 100644
--- a/java/com/google/gerrit/server/change/IncludedInRefs.java
+++ b/java/com/google/gerrit/server/change/IncludedInRefs.java
@@ -16,6 +16,7 @@
 
 import static java.util.stream.Collectors.toSet;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.permissions.PermissionBackend;
@@ -24,7 +25,6 @@
 import com.google.inject.Inject;
 import java.io.IOException;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -67,7 +67,7 @@
         }
       }
     }
-    return Collections.EMPTY_MAP;
+    return ImmutableMap.of();
   }
 
   private Set<Ref> getVisibleRefs(Repository repo, Set<String> refNames, Project.NameKey project)
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
index 7142137..d06940c 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
@@ -518,19 +518,29 @@
     }
   }
 
-  /** See {@link #updateRepo(RepoContext)} */
+  /**
+   * See {@link #updateRepo(RepoContext)}
+   *
+   * @param ctx context for the repository update
+   */
   protected void updateRepoImpl(RepoContext ctx) throws Exception {}
 
   /**
    * Returns a new patch set if one was created by the submit strategy, or null if not
    *
    * <p>See {@link #updateChange(ChangeContext)}
+   *
+   * @param ctx context for the change update
    */
   protected PatchSet updateChangeImpl(ChangeContext ctx) throws Exception {
     return null;
   }
 
-  /** See {@link #postUpdate(PostUpdateContext)} */
+  /**
+   * See {@link #postUpdate(PostUpdateContext)}
+   *
+   * @param ctx context for the post update
+   */
   protected void postUpdateImpl(PostUpdateContext ctx) throws Exception {}
 
   /** Amend the commit with gitlink update */
diff --git a/plugins/replication b/plugins/replication
index 687027a..98926b4 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit 687027a3f84e9d252b6970f953018da14006397c
+Subproject commit 98926b44a199b5a7049232f6c3b3758267368f8f