diff --git a/java/com/google/gerrit/acceptance/GerritServer.java b/java/com/google/gerrit/acceptance/GerritServer.java
index a48a278f71..ea63d737e2 100644
--- a/java/com/google/gerrit/acceptance/GerritServer.java
+++ b/java/com/google/gerrit/acceptance/GerritServer.java
@@ -259,6 +259,8 @@ public class GerritServer implements AutoCloseable {
           // Silence non-critical messages from JGit.
           .put("org.eclipse.jgit.transport.PacketLineIn", Level.WARN)
           .put("org.eclipse.jgit.transport.PacketLineOut", Level.WARN)
+          .put("org.eclipse.jgit.internal.storage.file.FileSnapshot", Level.WARN)
+          .put("org.eclipse.jgit.util.FS", Level.WARN)
           .build();
 
   private static boolean forceLocalDisk() {
diff --git a/java/com/google/gerrit/server/edit/ChangeEditModifier.java b/java/com/google/gerrit/server/edit/ChangeEditModifier.java
index fcd38c3435..661e376299 100644
--- a/java/com/google/gerrit/server/edit/ChangeEditModifier.java
+++ b/java/com/google/gerrit/server/edit/ChangeEditModifier.java
@@ -371,7 +371,7 @@ public class ChangeEditModifier {
     if (optionalChangeEdit.isPresent()) {
       ChangeEdit changeEdit = optionalChangeEdit.get();
       newTreeId = merge(repository, changeEdit, newTreeId);
-      if (ObjectId.equals(newTreeId, changeEdit.getEditCommit().getTree())) {
+      if (ObjectId.isEqual(newTreeId, changeEdit.getEditCommit().getTree())) {
         // Modifications are already contained in the change edit.
         return changeEdit;
       }
@@ -474,7 +474,7 @@ public class ChangeEditModifier {
     treeCreator.addTreeModifications(treeModifications);
     ObjectId newTreeId = treeCreator.createNewTreeAndGetId(repository);
 
-    if (ObjectId.equals(newTreeId, baseCommit.getTree())) {
+    if (ObjectId.isEqual(newTreeId, baseCommit.getTree())) {
       throw new InvalidChangeOperationException("no changes were made");
     }
     return newTreeId;
diff --git a/java/com/google/gerrit/server/edit/tree/ChangeFileContentModification.java b/java/com/google/gerrit/server/edit/tree/ChangeFileContentModification.java
index d91e2e8420..0adacd8461 100644
--- a/java/com/google/gerrit/server/edit/tree/ChangeFileContentModification.java
+++ b/java/com/google/gerrit/server/edit/tree/ChangeFileContentModification.java
@@ -23,6 +23,7 @@ import com.google.common.io.ByteStreams;
 import com.google.gerrit.extensions.restapi.RawInput;
 import java.io.IOException;
 import java.io.InputStream;
+import java.time.Instant;
 import java.util.Collections;
 import java.util.List;
 import org.eclipse.jgit.dircache.DirCacheEditor;
@@ -79,7 +80,7 @@ public class ChangeFileContentModification implements TreeModification {
       try {
         if (dirCacheEntry.getFileMode() == FileMode.GITLINK) {
           dirCacheEntry.setLength(0);
-          dirCacheEntry.setLastModified(0);
+          dirCacheEntry.setLastModified(Instant.EPOCH);
           ObjectId newObjectId = ObjectId.fromString(getNewContentBytes(), 0);
           dirCacheEntry.setObjectId(newObjectId);
         } else {
diff --git a/java/com/google/gerrit/server/patch/PatchListLoader.java b/java/com/google/gerrit/server/patch/PatchListLoader.java
index 08de537305..b639f96327 100644
--- a/java/com/google/gerrit/server/patch/PatchListLoader.java
+++ b/java/com/google/gerrit/server/patch/PatchListLoader.java
@@ -314,12 +314,12 @@ public class PatchListLoader implements Callable<PatchList> {
   }
 
   private static boolean areParentChild(RevCommit commitA, RevCommit commitB) {
-    return ObjectId.equals(commitA.getParent(0), commitB)
-        || ObjectId.equals(commitB.getParent(0), commitA);
+    return ObjectId.isEqual(commitA.getParent(0), commitB)
+        || ObjectId.isEqual(commitB.getParent(0), commitA);
   }
 
   private static boolean haveCommonParent(RevCommit commitA, RevCommit commitB) {
-    return ObjectId.equals(commitA.getParent(0), commitB.getParent(0));
+    return ObjectId.isEqual(commitA.getParent(0), commitB.getParent(0));
   }
 
   private static Set<String> getTouchedFilePaths(PatchListEntry patchListEntry) {
diff --git a/java/com/google/gerrit/sshd/commands/UploadArchive.java b/java/com/google/gerrit/sshd/commands/UploadArchive.java
index a58e472d10..c25a1a8f66 100644
--- a/java/com/google/gerrit/sshd/commands/UploadArchive.java
+++ b/java/com/google/gerrit/sshd/commands/UploadArchive.java
@@ -139,7 +139,7 @@ public class UploadArchive extends AbstractGitCommand {
     PacketLineIn packetIn = new PacketLineIn(in);
     for (; ; ) {
       String s = packetIn.readString();
-      if (isPacketLineEnd(s)) {
+      if (PacketLineIn.isEnd(s)) {
         break;
       }
       if (!s.startsWith(argCmd)) {
@@ -163,12 +163,6 @@ public class UploadArchive extends AbstractGitCommand {
     }
   }
 
-  // JGit API depends on reference equality with sentinel.
-  @SuppressWarnings({"ReferenceEquality", "StringEquality"})
-  private static boolean isPacketLineEnd(String s) {
-    return s == PacketLineIn.END;
-  }
-
   @Override
   protected void runImpl() throws IOException, PermissionBackendException, Failure {
     PacketLineOut packetOut = new PacketLineOut(out);