diff --git a/src/main/java/com/google/api/generator/engine/ast/BUILD.bazel b/src/main/java/com/google/api/generator/engine/ast/BUILD.bazel
index 3a8ff41fcf..a51125d5d4 100644
--- a/src/main/java/com/google/api/generator/engine/ast/BUILD.bazel
+++ b/src/main/java/com/google/api/generator/engine/ast/BUILD.bazel
@@ -20,6 +20,7 @@ java_library(
         "@com_google_auto_value_auto_value_annotations//jar",
         "@com_google_code_findbugs_jsr305//jar",
         "@com_google_guava_guava//jar",
+        "@com_google_protobuf//:protobuf_java",
         "@javax_validation_javax_validation_api//jar",
     ],
 )
diff --git a/src/main/java/com/google/api/generator/engine/ast/TypeNode.java b/src/main/java/com/google/api/generator/engine/ast/TypeNode.java
index 49fa35aaac..aef8f15727 100644
--- a/src/main/java/com/google/api/generator/engine/ast/TypeNode.java
+++ b/src/main/java/com/google/api/generator/engine/ast/TypeNode.java
@@ -17,6 +17,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import com.google.protobuf.ByteString;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
@@ -64,6 +65,9 @@ public enum TypeKind {
   public static final TypeNode SHORT_OBJECT =
       withReference(ConcreteReference.withClazz(Short.class));
 
+  public static final TypeNode BYTESTRING =
+      TypeNode.withReference(ConcreteReference.withClazz(ByteString.class));
+
   private static final Map<TypeNode, TypeNode> BOXED_TYPE_MAP = createBoxedTypeMap();
 
   public static final TypeNode VOID = builder().setTypeKind(TypeKind.VOID).build();
@@ -187,7 +191,7 @@ public boolean isPrimitiveType() {
   }
 
   public boolean isProtoPrimitiveType() {
-    return isPrimitiveType() || this.equals(TypeNode.STRING);
+    return isPrimitiveType() || this.equals(TypeNode.STRING) || this.equals(TypeNode.BYTESTRING);
   }
 
   public boolean isSupertypeOrEquals(TypeNode other) {
diff --git a/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java b/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
index fe4064ecee..1268cb7750 100644
--- a/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
+++ b/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
@@ -126,10 +126,10 @@ static Expr createDefaultValue(Field f) {
           PrimitiveValue.builder().setType(f.type()).setValue("true").build());
     }
 
-    if (f.type().equals(BYTESTRING_TYPE)) {
+    if (f.type().equals(TypeNode.BYTESTRING)) {
       return VariableExpr.builder()
-          .setStaticReferenceType(BYTESTRING_TYPE)
-          .setVariable(Variable.builder().setName("EMPTY").setType(BYTESTRING_TYPE).build())
+          .setStaticReferenceType(TypeNode.BYTESTRING)
+          .setVariable(Variable.builder().setName("EMPTY").setType(TypeNode.BYTESTRING).build())
           .build();
     }
 
diff --git a/src/main/java/com/google/api/generator/gapic/composer/ServiceClientTestClassComposer.java b/src/main/java/com/google/api/generator/gapic/composer/ServiceClientTestClassComposer.java
index 91acd082bc..3c18458963 100644
--- a/src/main/java/com/google/api/generator/gapic/composer/ServiceClientTestClassComposer.java
+++ b/src/main/java/com/google/api/generator/gapic/composer/ServiceClientTestClassComposer.java
@@ -494,6 +494,7 @@ private static MethodDefinition createRpcTestMethod(
               "No repeated field found for paged method %s with output message type %s",
               method.name(), methodOutputMessage.name()));
 
+      // Must be a non-repeated type.
       repeatedResponseType = repeatedPagedResultsField.type();
       responsesElementVarExpr =
           VariableExpr.withVariable(
@@ -506,7 +507,7 @@ private static MethodDefinition createRpcTestMethod(
                       Field.builder()
                           .setType(repeatedResponseType)
                           .setName("responsesElement")
-                          .setIsMessage(true)
+                          .setIsMessage(!repeatedResponseType.isProtoPrimitiveType())
                           .build()))
               .build());
     }
diff --git a/src/test/java/com/google/api/generator/gapic/composer/goldens/LoggingClientTest.golden b/src/test/java/com/google/api/generator/gapic/composer/goldens/LoggingClientTest.golden
index fb4ad5a543..044c5691fe 100644
--- a/src/test/java/com/google/api/generator/gapic/composer/goldens/LoggingClientTest.golden
+++ b/src/test/java/com/google/api/generator/gapic/composer/goldens/LoggingClientTest.golden
@@ -343,7 +343,7 @@ public class LoggingServiceV2ClientTest {
 
   @Test
   public void listLogsTest() throws Exception {
-    String responsesElement = String.newBuilder().build();
+    String responsesElement = "responsesElement-318365110";
     ListLogsResponse expectedResponse =
         ListLogsResponse.newBuilder()
             .setNextPageToken("")
@@ -387,7 +387,7 @@ public class LoggingServiceV2ClientTest {
 
   @Test
   public void listLogsTest2() throws Exception {
-    String responsesElement = String.newBuilder().build();
+    String responsesElement = "responsesElement-318365110";
     ListLogsResponse expectedResponse =
         ListLogsResponse.newBuilder()
             .setNextPageToken("")
@@ -431,7 +431,7 @@ public class LoggingServiceV2ClientTest {
 
   @Test
   public void listLogsTest3() throws Exception {
-    String responsesElement = String.newBuilder().build();
+    String responsesElement = "responsesElement-318365110";
     ListLogsResponse expectedResponse =
         ListLogsResponse.newBuilder()
             .setNextPageToken("")
@@ -475,7 +475,7 @@ public class LoggingServiceV2ClientTest {
 
   @Test
   public void listLogsTest4() throws Exception {
-    String responsesElement = String.newBuilder().build();
+    String responsesElement = "responsesElement-318365110";
     ListLogsResponse expectedResponse =
         ListLogsResponse.newBuilder()
             .setNextPageToken("")
@@ -519,7 +519,7 @@ public class LoggingServiceV2ClientTest {
 
   @Test
   public void listLogsTest5() throws Exception {
-    String responsesElement = String.newBuilder().build();
+    String responsesElement = "responsesElement-318365110";
     ListLogsResponse expectedResponse =
         ListLogsResponse.newBuilder()
             .setNextPageToken("")