diff --git a/google-cloud-bigquerystorage/clirr-ignored-differences.xml b/google-cloud-bigquerystorage/clirr-ignored-differences.xml
index c5f0600724..c55b8a691c 100644
--- a/google-cloud-bigquerystorage/clirr-ignored-differences.xml
+++ b/google-cloud-bigquerystorage/clirr-ignored-differences.xml
@@ -108,4 +108,38 @@
     <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
     <method>ConnectionWorkerPool(long, long, java.time.Duration, com.google.api.gax.batching.FlowController$LimitExceededBehavior, java.lang.String, com.google.cloud.bigquery.storage.v1.BigQueryWriteClient, boolean)</method>
   </difference>
+  <difference>
+    <differenceType>1001</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorker</className>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>ConnectionWorkerPool(long, long, java.time.Duration, com.google.api.gax.batching.FlowController$LimitExceededBehavior, java.lang.String, com.google.cloud.bigquery.storage.v1.BigQueryWriteClient, boolean)</method>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>com.google.api.core.ApiFuture append(com.google.cloud.bigquery.storage.v1.StreamWriter, com.google.cloud.bigquery.storage.v1.ProtoRows)</method>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>com.google.api.core.ApiFuture append(com.google.cloud.bigquery.storage.v1.StreamWriter, com.google.cloud.bigquery.storage.v1.ProtoRows, long)</method>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>void close(com.google.cloud.bigquery.storage.v1.StreamWriter)</method>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>void enableTestingLogic()</method>
+  </difference>
+  <difference>
+    <differenceType>7009</differenceType>
+    <className>com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool</className>
+    <method>long getInflightWaitSeconds(com.google.cloud.bigquery.storage.v1.StreamWriter)</method>
+  </difference>
 </differences>
diff --git a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorker.java b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorker.java
index 69aef0527c..573bc0c055 100644
--- a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorker.java
+++ b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorker.java
@@ -58,7 +58,7 @@
  *
  * <p>TODO: support updated schema
  */
-public class ConnectionWorker implements AutoCloseable {
+class ConnectionWorker implements AutoCloseable {
   private static final Logger log = Logger.getLogger(StreamWriter.class.getName());
 
   private Lock lock;
diff --git a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool.java b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool.java
index 7bcb358eea..0e6b5eab3a 100644
--- a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool.java
+++ b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/ConnectionWorkerPool.java
@@ -21,6 +21,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.cloud.bigquery.storage.v1.ConnectionWorker.Load;
 import com.google.cloud.bigquery.storage.v1.ConnectionWorker.TableSchemaAndTimestamp;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Stopwatch;
 import com.google.common.collect.ImmutableList;
@@ -192,7 +193,7 @@ public abstract static class Builder {
   /** Static setting for connection pool. */
   private static Settings settings = Settings.builder().build();
 
-  public ConnectionWorkerPool(
+  ConnectionWorkerPool(
       long maxInflightRequests,
       long maxInflightBytes,
       java.time.Duration maxRetryDuration,
@@ -218,13 +219,12 @@ public static void setOptions(Settings settings) {
   }
 
   /** Distributes the writing of a message to an underlying connection. */
-  public ApiFuture<AppendRowsResponse> append(StreamWriter streamWriter, ProtoRows rows) {
+  ApiFuture<AppendRowsResponse> append(StreamWriter streamWriter, ProtoRows rows) {
     return append(streamWriter, rows, -1);
   }
 
   /** Distributes the writing of a message to an underlying connection. */
-  public ApiFuture<AppendRowsResponse> append(
-      StreamWriter streamWriter, ProtoRows rows, long offset) {
+  ApiFuture<AppendRowsResponse> append(StreamWriter streamWriter, ProtoRows rows, long offset) {
     // We are in multiplexing mode after entering the following logic.
     ConnectionWorker connectionWorker;
     lock.lock();
@@ -371,7 +371,7 @@ private ConnectionWorker createConnectionWorker(String streamName, ProtoSchema w
    * <p>The corresponding worker is not closed until there is no stream reference is targeting to
    * that worker.
    */
-  public void close(StreamWriter streamWriter) {
+  void close(StreamWriter streamWriter) {
     lock.lock();
     try {
       streamWriterToConnection.remove(streamWriter);
@@ -403,7 +403,7 @@ public void close(StreamWriter streamWriter) {
   }
 
   /** Fetch the wait seconds from corresponding worker. */
-  public long getInflightWaitSeconds(StreamWriter streamWriter) {
+  long getInflightWaitSeconds(StreamWriter streamWriter) {
     lock.lock();
     try {
       ConnectionWorker connectionWorker = streamWriterToConnection.get(streamWriter);
@@ -422,7 +422,8 @@ TableSchemaAndTimestamp getUpdatedSchema(StreamWriter streamWriter) {
   }
 
   /** Enable Test related logic. */
-  public static void enableTestingLogic() {
+  @VisibleForTesting
+  static void enableTestingLogic() {
     enableTesting = true;
   }