diff --git a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Publisher.java b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Publisher.java
index 352822a71b35..115451096e97 100644
--- a/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Publisher.java
+++ b/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Publisher.java
@@ -471,8 +471,8 @@ public static final class Builder {
     static final long DEFAULT_ELEMENT_COUNT_THRESHOLD = 100L;
     static final long DEFAULT_REQUEST_BYTES_THRESHOLD = 1000L; // 1 kB
     static final Duration DEFAULT_DELAY_THRESHOLD = Duration.ofMillis(1);
-    static final Duration DEFAULT_RPC_TIMEOUT = Duration.ofSeconds(10);
-    static final Duration DEFAULT_TOTAL_TIMEOUT = MIN_TOTAL_TIMEOUT;
+    private static final Duration DEFAULT_RPC_TIMEOUT = Duration.ofSeconds(10);
+    private static final Duration DEFAULT_TOTAL_TIMEOUT = MIN_TOTAL_TIMEOUT;
     static final BatchingSettings DEFAULT_BATCHING_SETTINGS =
         BatchingSettings.newBuilder()
             .setDelayThreshold(DEFAULT_DELAY_THRESHOLD)
@@ -503,17 +503,17 @@ public static final class Builder {
 
     RetrySettings retrySettings = DEFAULT_RETRY_SETTINGS;
 
-    TransportChannelProvider channelProvider =
+    private TransportChannelProvider channelProvider =
         TopicAdminSettings.defaultGrpcTransportProviderBuilder().setChannelsPerCpu(1).build();
 
-    HeaderProvider headerProvider = new NoHeaderProvider();
-    HeaderProvider internalHeaderProvider =
+    private HeaderProvider headerProvider = new NoHeaderProvider();
+    private HeaderProvider internalHeaderProvider =
         TopicAdminSettings.defaultApiClientHeaderProviderBuilder().build();
     ExecutorProvider executorProvider = DEFAULT_EXECUTOR_PROVIDER;
-    CredentialsProvider credentialsProvider =
+    private CredentialsProvider credentialsProvider =
         TopicAdminSettings.defaultCredentialsProviderBuilder().build();
 
-    ApiFunction<PubsubMessage, PubsubMessage> messageTransform =
+    private ApiFunction<PubsubMessage, PubsubMessage> messageTransform =
         new ApiFunction<PubsubMessage, PubsubMessage>() {
           @Override
           public PubsubMessage apply(PubsubMessage input) {