diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/api/PluginLoader.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/api/PluginLoader.java
index 8a479dd896..de25ef0814 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/api/PluginLoader.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/api/PluginLoader.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.client.api;
 
+import static java.util.stream.Collectors.toList;
+
 import com.google.gerrit.client.ErrorDialog;
 import com.google.gerrit.client.Gerrit;
 import com.google.gerrit.client.VoidResult;
@@ -28,7 +30,6 @@ import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.DialogBox;
 import com.google.gwtexpui.progress.client.ProgressBar;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /** Loads JavaScript plugins with a progress meter visible. */
 public class PluginLoader extends DialogBox {
@@ -39,7 +40,7 @@ public class PluginLoader extends DialogBox {
     if (plugins == null || plugins.isEmpty()) {
       callback.onSuccess(VoidResult.create());
     } else {
-      plugins = plugins.stream().filter(p -> p.endsWith(".js")).collect(Collectors.toList());
+      plugins = plugins.stream().filter(p -> p.endsWith(".js")).collect(toList());
       if (plugins.isEmpty()) {
         callback.onSuccess(VoidResult.create());
       } else {
diff --git a/java/com/google/gerrit/acceptance/AbstractNotificationTest.java b/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
index f42b622639..ab887fe7c1 100644
--- a/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
@@ -18,6 +18,7 @@ import static com.google.common.truth.Truth.assertAbout;
 import static com.google.gerrit.extensions.api.changes.RecipientType.BCC;
 import static com.google.gerrit.extensions.api.changes.RecipientType.CC;
 import static com.google.gerrit.extensions.api.changes.RecipientType.TO;
+import static java.util.stream.Collectors.toList;
 
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
@@ -48,7 +49,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.junit.TestRepository;
 import org.junit.After;
 import org.junit.Before;
@@ -121,7 +121,7 @@ public abstract class AbstractNotificationTest extends AbstractDaemonTest {
               .stream()
               .map(Address::getEmail)
               .filter(e -> !recipients.get(TO).contains(e) && !recipients.get(CC).contains(e))
-              .collect(Collectors.toList()));
+              .collect(toList()));
       this.users = users;
       if (!message.headers().containsKey("X-Gerrit-MessageType")) {
         fail("a message was sent with X-Gerrit-MessageType header");
@@ -162,7 +162,7 @@ public abstract class AbstractNotificationTest extends AbstractDaemonTest {
       }
       Truth.assertThat(header).isInstanceOf(AddressList.class);
       AddressList addrList = (AddressList) header;
-      return addrList.getAddressList().stream().map(Address::getEmail).collect(Collectors.toList());
+      return addrList.getAddressList().stream().map(Address::getEmail).collect(toList());
     }
 
     public FakeEmailSenderSubject to(String... emails) {
diff --git a/java/com/google/gerrit/acceptance/LightweightPluginDaemonTest.java b/java/com/google/gerrit/acceptance/LightweightPluginDaemonTest.java
index 58a9238f7c..7f932c3a73 100644
--- a/java/com/google/gerrit/acceptance/LightweightPluginDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/LightweightPluginDaemonTest.java
@@ -20,12 +20,16 @@ import com.google.gerrit.server.plugins.TestServerPlugin;
 import com.google.inject.Inject;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
+import org.junit.rules.TemporaryFolder;
 
 public class LightweightPluginDaemonTest extends AbstractDaemonTest {
   @Inject private PluginGuiceEnvironment env;
 
   @Inject private PluginUser.Factory pluginUserFactory;
 
+  @Rule public TemporaryFolder tempDataDir = new TemporaryFolder();
+
   private TestServerPlugin plugin;
 
   @Before
@@ -40,7 +44,8 @@ public class LightweightPluginDaemonTest extends AbstractDaemonTest {
             getClass().getClassLoader(),
             testPlugin.sysModule(),
             testPlugin.httpModule(),
-            testPlugin.sshModule());
+            testPlugin.sshModule(),
+            tempDataDir.getRoot().toPath());
 
     plugin.start(env);
     env.onStartPlugin(plugin);
diff --git a/java/com/google/gerrit/server/fixes/FixReplacementInterpreter.java b/java/com/google/gerrit/server/fixes/FixReplacementInterpreter.java
index 3fc786b417..1e5088bef9 100644
--- a/java/com/google/gerrit/server/fixes/FixReplacementInterpreter.java
+++ b/java/com/google/gerrit/server/fixes/FixReplacementInterpreter.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.fixes;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.stream.Collectors.groupingBy;
 
 import com.google.gerrit.common.RawInputUtil;
 import com.google.gerrit.extensions.restapi.BinaryResult;
@@ -33,7 +34,6 @@ import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
 
@@ -73,9 +73,7 @@ public class FixReplacementInterpreter {
     checkNotNull(fixReplacements, "Fix replacements must not be null");
 
     Map<String, List<FixReplacement>> fixReplacementsPerFilePath =
-        fixReplacements
-            .stream()
-            .collect(Collectors.groupingBy(fixReplacement -> fixReplacement.path));
+        fixReplacements.stream().collect(groupingBy(fixReplacement -> fixReplacement.path));
 
     List<TreeModification> treeModifications = new ArrayList<>();
     for (Map.Entry<String, List<FixReplacement>> entry : fixReplacementsPerFilePath.entrySet()) {
diff --git a/java/com/google/gerrit/server/git/strategy/SubmitDryRun.java b/java/com/google/gerrit/server/git/strategy/SubmitDryRun.java
index c76a59ad1c..3a954fb959 100644
--- a/java/com/google/gerrit/server/git/strategy/SubmitDryRun.java
+++ b/java/com/google/gerrit/server/git/strategy/SubmitDryRun.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.git.strategy;
 
+import static java.util.stream.Collectors.toSet;
+
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import com.google.gerrit.extensions.client.SubmitType;
@@ -31,7 +33,6 @@ import java.io.IOException;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
@@ -68,7 +69,7 @@ public class SubmitDryRun {
             repo.getRefDatabase().getRefs(Constants.R_TAGS).values().stream())
         .map(Ref::getObjectId)
         .filter(o -> o != null)
-        .collect(Collectors.toSet());
+        .collect(toSet());
   }
 
   public static Set<RevCommit> getAlreadyAccepted(Repository repo, RevWalk rw) throws IOException {
diff --git a/java/com/google/gerrit/server/mail/ListMailFilter.java b/java/com/google/gerrit/server/mail/ListMailFilter.java
index a88a0e4b3d..21347cb956 100644
--- a/java/com/google/gerrit/server/mail/ListMailFilter.java
+++ b/java/com/google/gerrit/server/mail/ListMailFilter.java
@@ -14,13 +14,14 @@
 
 package com.google.gerrit.server.mail;
 
+import static java.util.stream.Collectors.joining;
+
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.mail.receive.MailMessage;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.util.Arrays;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.lib.Config;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -42,7 +43,7 @@ public class ListMailFilter implements MailFilter {
   ListMailFilter(@GerritServerConfig Config cfg) {
     this.mode = cfg.getEnum("receiveemail", "filter", "mode", ListFilterMode.OFF);
     String[] addresses = cfg.getStringList("receiveemail", "filter", "patterns");
-    String concat = Arrays.asList(addresses).stream().collect(Collectors.joining("|"));
+    String concat = Arrays.asList(addresses).stream().collect(joining("|"));
     this.mailPattern = Pattern.compile(concat);
   }
 
diff --git a/java/com/google/gerrit/server/notedb/DeleteCommentRewriter.java b/java/com/google/gerrit/server/notedb/DeleteCommentRewriter.java
index 3264be2bb2..db7b86a022 100644
--- a/java/com/google/gerrit/server/notedb/DeleteCommentRewriter.java
+++ b/java/com/google/gerrit/server/notedb/DeleteCommentRewriter.java
@@ -17,6 +17,7 @@ package com.google.gerrit.server.notedb;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.gerrit.reviewdb.client.PatchLineComment.Status.PUBLISHED;
 import static java.util.stream.Collectors.toList;
+import static java.util.stream.Collectors.toMap;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -31,7 +32,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.CommitBuilder;
 import org.eclipse.jgit.lib.ObjectId;
@@ -139,7 +139,7 @@ public class DeleteCommentRewriter implements NoteDbRewriter {
         .values()
         .stream()
         .flatMap(n -> n.getComments().stream())
-        .collect(Collectors.toMap(c -> c.key.uuid, c -> c));
+        .collect(toMap(c -> c.key.uuid, c -> c));
   }
 
   /**
diff --git a/java/com/google/gerrit/server/patch/IntraLineDiff.java b/java/com/google/gerrit/server/patch/IntraLineDiff.java
index ee8b88b7f4..a1823359e5 100644
--- a/java/com/google/gerrit/server/patch/IntraLineDiff.java
+++ b/java/com/google/gerrit/server/patch/IntraLineDiff.java
@@ -18,6 +18,7 @@ import static com.google.gerrit.server.ioutil.BasicSerialization.readEnum;
 import static com.google.gerrit.server.ioutil.BasicSerialization.readVarInt32;
 import static com.google.gerrit.server.ioutil.BasicSerialization.writeEnum;
 import static com.google.gerrit.server.ioutil.BasicSerialization.writeVarInt32;
+import static java.util.stream.Collectors.toList;
 
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.reviewdb.client.CodedEnum;
@@ -30,7 +31,6 @@ import java.io.Serializable;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.diff.Edit;
 import org.eclipse.jgit.diff.ReplaceEdit;
 
@@ -109,7 +109,7 @@ public class IntraLineDiff implements Serializable {
         for (int j = 0; j < innerCount; j++) {
           inner[j] = readEdit(in);
         }
-        editArray[i] = new ReplaceEdit(editArray[i], toList(inner));
+        editArray[i] = new ReplaceEdit(editArray[i], asList(inner));
       }
     }
     edits = ImmutableList.copyOf(editArray);
@@ -128,7 +128,7 @@ public class IntraLineDiff implements Serializable {
 
   private static ReplaceEdit copy(ReplaceEdit edit) {
     List<Edit> internalEdits =
-        edit.getInternalEdits().stream().map(IntraLineDiff::copy).collect(Collectors.toList());
+        edit.getInternalEdits().stream().map(IntraLineDiff::copy).collect(toList());
     return new ReplaceEdit(
         edit.getBeginA(), edit.getEndA(), edit.getBeginB(), edit.getEndB(), internalEdits);
   }
@@ -148,7 +148,7 @@ public class IntraLineDiff implements Serializable {
     return new Edit(beginA, endA, beginB, endB);
   }
 
-  private static List<Edit> toList(Edit[] l) {
+  private static List<Edit> asList(Edit[] l) {
     return Collections.unmodifiableList(Arrays.asList(l));
   }
 }
diff --git a/java/com/google/gerrit/server/plugins/ListPlugins.java b/java/com/google/gerrit/server/plugins/ListPlugins.java
index 9a42bb9188..989e839646 100644
--- a/java/com/google/gerrit/server/plugins/ListPlugins.java
+++ b/java/com/google/gerrit/server/plugins/ListPlugins.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.plugins;
 
 import static java.util.Comparator.comparing;
+import static java.util.stream.Collectors.toMap;
 
 import com.google.common.collect.Streams;
 import com.google.gerrit.common.data.GlobalCapability;
@@ -30,7 +31,6 @@ import java.util.Locale;
 import java.util.SortedMap;
 import java.util.TreeMap;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.kohsuke.args4j.Option;
 
@@ -137,7 +137,7 @@ public class ListPlugins implements RestReadView<TopLevelResource> {
     if (limit > 0) {
       s = s.limit(limit);
     }
-    return new TreeMap<>(s.collect(Collectors.toMap(p -> p.getName(), p -> toPluginInfo(p))));
+    return new TreeMap<>(s.collect(toMap(p -> p.getName(), p -> toPluginInfo(p))));
   }
 
   private void checkMatchOptions(boolean cond) throws BadRequestException {
diff --git a/java/com/google/gerrit/server/plugins/TestServerPlugin.java b/java/com/google/gerrit/server/plugins/TestServerPlugin.java
index 6897b9a647..dbdc57694d 100644
--- a/java/com/google/gerrit/server/plugins/TestServerPlugin.java
+++ b/java/com/google/gerrit/server/plugins/TestServerPlugin.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.plugins;
 
 import com.google.gerrit.server.PluginUser;
+import java.nio.file.Path;
 
 public class TestServerPlugin extends ServerPlugin {
   private final ClassLoader classLoader;
@@ -29,9 +30,10 @@ public class TestServerPlugin extends ServerPlugin {
       ClassLoader classloader,
       String sysName,
       String httpName,
-      String sshName)
+      String sshName,
+      Path dataDir)
       throws InvalidPluginException {
-    super(name, pluginCanonicalWebUrl, user, null, null, null, null, classloader);
+    super(name, pluginCanonicalWebUrl, user, null, null, null, dataDir, classloader);
     this.classLoader = classloader;
     this.sysName = sysName;
     this.httpName = httpName;
diff --git a/java/com/google/gerrit/server/project/ProjectJson.java b/java/com/google/gerrit/server/project/ProjectJson.java
index 6f15c7dfd8..f2a93d33d9 100644
--- a/java/com/google/gerrit/server/project/ProjectJson.java
+++ b/java/com/google/gerrit/server/project/ProjectJson.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.project;
 
+import static java.util.stream.Collectors.toMap;
+
 import com.google.common.base.Strings;
 import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.LabelValue;
@@ -28,7 +30,6 @@ import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.util.HashMap;
 import java.util.List;
-import java.util.stream.Collectors;
 
 @Singleton
 public class ProjectJson {
@@ -48,9 +49,7 @@ public class ProjectJson {
     for (LabelType t : projectState.getLabelTypes().getLabelTypes()) {
       LabelTypeInfo labelInfo = new LabelTypeInfo();
       labelInfo.values =
-          t.getValues()
-              .stream()
-              .collect(Collectors.toMap(LabelValue::formatValue, LabelValue::getText));
+          t.getValues().stream().collect(toMap(LabelValue::formatValue, LabelValue::getText));
       labelInfo.defaultValue = t.getDefaultValue();
       info.labels.put(t.getName(), labelInfo);
     }
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index bcfd53cf8a..ebb3e659a0 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -89,7 +89,6 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.eclipse.jgit.lib.Config;
@@ -1244,7 +1243,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
     }
 
     List<Predicate<ChangeData>> predicates =
-        parts.stream().map(fullPredicateFunc).collect(Collectors.toList());
+        parts.stream().map(fullPredicateFunc).collect(toList());
     return Predicate.and(predicates);
   }
 
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index 2b1b3132ea..cc4e2a7ddb 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -49,6 +49,7 @@ import static com.google.gerrit.server.project.testing.Util.category;
 import static com.google.gerrit.server.project.testing.Util.value;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.concurrent.TimeUnit.SECONDS;
+import static java.util.stream.Collectors.joining;
 import static java.util.stream.Collectors.toList;
 import static java.util.stream.Collectors.toSet;
 
@@ -154,7 +155,6 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
 import org.eclipse.jgit.junit.TestRepository;
@@ -461,7 +461,7 @@ public class ChangeIT extends AbstractDaemonTest {
     assertThat(result.reviewers).isNotEmpty();
     ChangeInfo info = gApi.changes().id(changeId).get();
     Function<Collection<AccountInfo>, Collection<String>> toEmails =
-        ais -> ais.stream().map(ai -> ai.email).collect(Collectors.toSet());
+        ais -> ais.stream().map(ai -> ai.email).collect(toSet());
     assertThat(toEmails.apply(info.pendingReviewers.get(REVIEWER)))
         .containsExactly(
             admin.email, user1.email, user2.email, "byemail1@example.com", "byemail2@example.com");
@@ -3230,7 +3230,7 @@ public class ChangeIT extends AbstractDaemonTest {
   @Test
   public void putTopicExceedLimitFails() throws Exception {
     String changeId = createChange().getChangeId();
-    String topic = Stream.generate(() -> "t").limit(2049).collect(Collectors.joining());
+    String topic = Stream.generate(() -> "t").limit(2049).collect(joining());
 
     exception.expect(BadRequestException.class);
     exception.expectMessage("topic length exceeds the limit");
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
index f3e9a1925f..060cef5c66 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
@@ -19,6 +19,8 @@ import static com.google.common.truth.TruthJUnit.assume;
 import static com.google.gerrit.extensions.common.testing.DiffInfoSubject.assertThat;
 import static com.google.gerrit.extensions.common.testing.FileInfoSubject.assertThat;
 import static com.google.gerrit.reviewdb.client.Patch.COMMIT_MSG;
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toMap;
 
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableMap;
@@ -44,7 +46,6 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import javax.imageio.ImageIO;
 import org.eclipse.jgit.lib.Config;
@@ -64,7 +65,7 @@ public class RevisionDiffIT extends AbstractDaemonTest {
   private static final String FILE_CONTENT =
       IntStream.rangeClosed(1, 100)
           .mapToObj(number -> String.format("Line %d\n", number))
-          .collect(Collectors.joining());
+          .collect(joining());
   private static final String FILE_CONTENT2 = "1st line\n2nd line\n3rd line\n";
 
   private boolean intraline;
@@ -1286,7 +1287,7 @@ public class RevisionDiffIT extends AbstractDaemonTest {
     testRepo.reset(parentCommit);
     Map<String, String> files =
         Arrays.stream(removedFilePaths)
-            .collect(Collectors.toMap(Function.identity(), path -> "Irrelevant content"));
+            .collect(toMap(Function.identity(), path -> "Irrelevant content"));
     PushOneCommit push =
         pushFactory.create(db, admin.getIdent(), testRepo, "Remove files from repo", files);
     PushOneCommit.Result result = push.rm("refs/for/master");
diff --git a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
index 7b86a968f7..9670b34162 100644
--- a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
+++ b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
@@ -93,7 +93,6 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.junit.TestRepository;
@@ -353,14 +352,14 @@ public abstract class AbstractPushForReview extends AbstractDaemonTest {
 
   @Test
   public void pushForMasterWithTopicInRefExceedLimitFails() throws Exception {
-    String topic = Stream.generate(() -> "t").limit(2049).collect(Collectors.joining());
+    String topic = Stream.generate(() -> "t").limit(2049).collect(joining());
     PushOneCommit.Result r = pushTo("refs/for/master/" + topic);
     r.assertErrorStatus("topic length exceeds the limit (2048)");
   }
 
   @Test
   public void pushForMasterWithTopicAsOptionExceedLimitFails() throws Exception {
-    String topic = Stream.generate(() -> "t").limit(2049).collect(Collectors.joining());
+    String topic = Stream.generate(() -> "t").limit(2049).collect(joining());
     PushOneCommit.Result r = pushTo("refs/for/master%topic=" + topic);
     r.assertErrorStatus("topic length exceeds the limit (2048)");
   }
diff --git a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
index 4c5f23151c..7b361268b7 100644
--- a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
@@ -18,6 +18,8 @@ import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth8.assertThat;
 import static com.google.gerrit.acceptance.PushOneCommit.FILE_NAME;
 import static com.google.gerrit.acceptance.PushOneCommit.SUBJECT;
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.toList;
 
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
@@ -68,7 +70,6 @@ import java.util.Optional;
 import java.util.function.Supplier;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
@@ -962,7 +963,7 @@ public class CommentsIT extends AbstractDaemonTest {
         .values()
         .stream()
         .flatMap(List::stream)
-        .collect(Collectors.toList());
+        .collect(toList());
   }
 
   private CommentInput addComment(String changeId, String message) throws Exception {
@@ -976,7 +977,7 @@ public class CommentsIT extends AbstractDaemonTest {
   private void addComments(String changeId, String revision, CommentInput... commentInputs)
       throws Exception {
     ReviewInput input = new ReviewInput();
-    input.comments = Arrays.stream(commentInputs).collect(Collectors.groupingBy(c -> c.path));
+    input.comments = Arrays.stream(commentInputs).collect(groupingBy(c -> c.path));
     gApi.changes().id(changeId).revision(revision).review(input);
   }