diff --git a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockIAMPolicyImpl.java b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockIAMPolicyImpl.java
index e1630035f35f..4461c56653aa 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockIAMPolicyImpl.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockIAMPolicyImpl.java
@@ -32,7 +32,7 @@
 @javax.annotation.Generated("by GAPIC")
 @BetaApi
 public class MockIAMPolicyImpl extends IAMPolicyImplBase {
-  private ArrayList<AbstractMessage> requests;
+  private List<AbstractMessage> requests;
   private Queue<Object> responses;
 
   public MockIAMPolicyImpl() {
diff --git a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockPublisherImpl.java b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockPublisherImpl.java
index 48f215c9bb49..65a379ff7f99 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockPublisherImpl.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockPublisherImpl.java
@@ -38,7 +38,7 @@
 @javax.annotation.Generated("by GAPIC")
 @BetaApi
 public class MockPublisherImpl extends PublisherImplBase {
-  private ArrayList<AbstractMessage> requests;
+  private List<AbstractMessage> requests;
   private Queue<Object> responses;
 
   public MockPublisherImpl() {
diff --git a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockSubscriberImpl.java b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockSubscriberImpl.java
index 2ade2858d4a6..c59de7ed7c91 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockSubscriberImpl.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/test/java/com/google/cloud/pubsub/v1/MockSubscriberImpl.java
@@ -49,7 +49,7 @@
 @javax.annotation.Generated("by GAPIC")
 @BetaApi
 public class MockSubscriberImpl extends SubscriberImplBase {
-  private ArrayList<AbstractMessage> requests;
+  private List<AbstractMessage> requests;
   private Queue<Object> responses;
 
   public MockSubscriberImpl() {
diff --git a/google-cloud-clients/google-cloud-pubsub/synth.metadata b/google-cloud-clients/google-cloud-pubsub/synth.metadata
index 1261449337fb..3b65f35f62bc 100644
--- a/google-cloud-clients/google-cloud-pubsub/synth.metadata
+++ b/google-cloud-clients/google-cloud-pubsub/synth.metadata
@@ -1,19 +1,19 @@
 {
-  "updateTime": "2019-03-30T07:50:27.552803Z",
+  "updateTime": "2019-04-02T07:51:42.879133Z",
   "sources": [
     {
       "generator": {
         "name": "artman",
-        "version": "0.16.21",
-        "dockerImage": "googleapis/artman@sha256:854131ec1af7b3a313253474c24748dc0acd217a58a0b74dbfb559f340a15d78"
+        "version": "0.16.22",
+        "dockerImage": "googleapis/artman@sha256:e7f9554322a8aa1416c122c918fdc4cdec8cfe816f027fc948dec0be7edef320"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "fd67be4b51a8c809b97100ccf1c3cffd15b85d7b",
-        "internalRef": "241096997"
+        "sha": "6c48ab5aef47dc14e02e2dc718d232a28067129d",
+        "internalRef": "241437588"
       }
     }
   ],