diff --git a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
index 4214080d9433..612fbb6b44a9 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
@@ -292,7 +292,9 @@ public String extractNextToken(ListTopicsResponse payload) {
 
             @Override
             public Iterable<Topic> extractResources(ListTopicsResponse payload) {
-              return payload.getTopicsList();
+              return payload.getTopicsList() != null
+                  ? payload.getTopicsList()
+                  : ImmutableList.<Topic>of();
             }
           };
 
@@ -332,7 +334,9 @@ public String extractNextToken(ListTopicSubscriptionsResponse payload) {
 
             @Override
             public Iterable<String> extractResources(ListTopicSubscriptionsResponse payload) {
-              return payload.getSubscriptionsList();
+              return payload.getSubscriptionsList() != null
+                  ? payload.getSubscriptionsList()
+                  : ImmutableList.<String>of();
             }
           };
 
@@ -476,11 +480,6 @@ public static class Builder extends StubSettings.Builder<PublisherStubSettings,
           ImmutableSet.copyOf(
               Lists.<StatusCode.Code>newArrayList(
                   StatusCode.Code.DEADLINE_EXCEEDED, StatusCode.Code.UNAVAILABLE)));
-      definitions.put(
-          "http_get",
-          ImmutableSet.copyOf(
-              Lists.<StatusCode.Code>newArrayList(
-                  StatusCode.Code.DEADLINE_EXCEEDED, StatusCode.Code.UNAVAILABLE)));
       definitions.put("non_idempotent", ImmutableSet.copyOf(Lists.<StatusCode.Code>newArrayList()));
       definitions.put(
           "one_plus_delivery",
diff --git a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
index 7072eb0a55eb..d66dca70da74 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
@@ -355,7 +355,9 @@ public String extractNextToken(ListSubscriptionsResponse payload) {
 
             @Override
             public Iterable<Subscription> extractResources(ListSubscriptionsResponse payload) {
-              return payload.getSubscriptionsList();
+              return payload.getSubscriptionsList() != null
+                  ? payload.getSubscriptionsList()
+                  : ImmutableList.<Subscription>of();
             }
           };
 
@@ -389,7 +391,9 @@ public String extractNextToken(ListSnapshotsResponse payload) {
 
             @Override
             public Iterable<Snapshot> extractResources(ListSnapshotsResponse payload) {
-              return payload.getSnapshotsList();
+              return payload.getSnapshotsList() != null
+                  ? payload.getSnapshotsList()
+                  : ImmutableList.<Snapshot>of();
             }
           };
 
@@ -484,11 +488,6 @@ public static class Builder extends StubSettings.Builder<SubscriberStubSettings,
                   StatusCode.Code.INTERNAL,
                   StatusCode.Code.RESOURCE_EXHAUSTED,
                   StatusCode.Code.UNAVAILABLE)));
-      definitions.put(
-          "http_get",
-          ImmutableSet.copyOf(
-              Lists.<StatusCode.Code>newArrayList(
-                  StatusCode.Code.DEADLINE_EXCEEDED, StatusCode.Code.UNAVAILABLE)));
       definitions.put("non_idempotent", ImmutableSet.copyOf(Lists.<StatusCode.Code>newArrayList()));
       RETRYABLE_CODE_DEFINITIONS = definitions.build();
     }
diff --git a/google-cloud-clients/google-cloud-pubsub/synth.py b/google-cloud-clients/google-cloud-pubsub/synth.py
index f8862c71e023..0601c96b8bb0 100644
--- a/google-cloud-clients/google-cloud-pubsub/synth.py
+++ b/google-cloud-clients/google-cloud-pubsub/synth.py
@@ -35,6 +35,12 @@
   s.copy(library / f'grpc-google-cloud-{service}-{version}/src', f'../../google-api-grpc/grpc-google-cloud-{service}-{version}/src')
   s.copy(library / f'proto-google-cloud-{service}-{version}/src', f'../../google-api-grpc/proto-google-cloud-{service}-{version}/src')
 
+  s.replace(
+      '**/stub/SubscriberStubSettings.java',
+      r'return InstantiatingGrpcChannelProvider\.newBuilder\(\);',
+      'return InstantiatingGrpcChannelProvider.newBuilder().setMaxInboundMessageSize(20 << 20); // 20MB'
+  )
+
   java.format_code('./src')
   java.format_code(f'../../google-api-grpc/grpc-google-cloud-{service}-{version}/src')
   java.format_code(f'../../google-api-grpc/proto-google-cloud-{service}-{version}/src')