diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/AuditConfigDelta.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/AuditConfigDelta.java
index f4e3194f..b1f2b2dc 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/AuditConfigDelta.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/AuditConfigDelta.java
@@ -508,13 +508,13 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (action_ != com.google.iam.v1.AuditConfigDelta.Action.ACTION_UNSPECIFIED.getNumber()) {
       output.writeEnum(1, action_);
     }
-    if (!getServiceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(service_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 2, service_);
     }
-    if (!getExemptedMemberBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(exemptedMember_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 3, exemptedMember_);
     }
-    if (!getLogTypeBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(logType_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 4, logType_);
     }
     unknownFields.writeTo(output);
@@ -529,13 +529,13 @@ public int getSerializedSize() {
     if (action_ != com.google.iam.v1.AuditConfigDelta.Action.ACTION_UNSPECIFIED.getNumber()) {
       size += com.google.protobuf.CodedOutputStream.computeEnumSize(1, action_);
     }
-    if (!getServiceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(service_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, service_);
     }
-    if (!getExemptedMemberBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(exemptedMember_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, exemptedMember_);
     }
-    if (!getLogTypeBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(logType_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, logType_);
     }
     size += unknownFields.getSerializedSize();
diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/Binding.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/Binding.java
index 394a969b..b85e8407 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/Binding.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/Binding.java
@@ -370,7 +370,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    if (!getRoleBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(role_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, role_);
     }
     for (int i = 0; i < members_.size(); i++) {
@@ -388,7 +388,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!getRoleBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(role_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, role_);
     }
     {
diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/BindingDelta.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/BindingDelta.java
index c5557b73..ed69378d 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/BindingDelta.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/BindingDelta.java
@@ -504,10 +504,10 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (action_ != com.google.iam.v1.BindingDelta.Action.ACTION_UNSPECIFIED.getNumber()) {
       output.writeEnum(1, action_);
     }
-    if (!getRoleBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(role_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 2, role_);
     }
-    if (!getMemberBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(member_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 3, member_);
     }
     if (condition_ != null) {
@@ -525,10 +525,10 @@ public int getSerializedSize() {
     if (action_ != com.google.iam.v1.BindingDelta.Action.ACTION_UNSPECIFIED.getNumber()) {
       size += com.google.protobuf.CodedOutputStream.computeEnumSize(1, action_);
     }
-    if (!getRoleBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(role_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, role_);
     }
-    if (!getMemberBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(member_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, member_);
     }
     if (condition_ != null) {
diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/GetIamPolicyRequest.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/GetIamPolicyRequest.java
index b4b3a7af..6f21bb3e 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/GetIamPolicyRequest.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/GetIamPolicyRequest.java
@@ -244,7 +244,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, resource_);
     }
     if (options_ != null) {
@@ -259,7 +259,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, resource_);
     }
     if (options_ != null) {
diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/SetIamPolicyRequest.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/SetIamPolicyRequest.java
index d5df476e..91de98ad 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/SetIamPolicyRequest.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/SetIamPolicyRequest.java
@@ -249,7 +249,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, resource_);
     }
     if (policy_ != null) {
@@ -264,7 +264,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, resource_);
     }
     if (policy_ != null) {
diff --git a/proto-google-iam-v1/src/main/java/com/google/iam/v1/TestIamPermissionsRequest.java b/proto-google-iam-v1/src/main/java/com/google/iam/v1/TestIamPermissionsRequest.java
index 081420de..5fdcc731 100644
--- a/proto-google-iam-v1/src/main/java/com/google/iam/v1/TestIamPermissionsRequest.java
+++ b/proto-google-iam-v1/src/main/java/com/google/iam/v1/TestIamPermissionsRequest.java
@@ -268,7 +268,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, resource_);
     }
     for (int i = 0; i < permissions_.size(); i++) {
@@ -283,7 +283,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!getResourceBytes().isEmpty()) {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(resource_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, resource_);
     }
     {
diff --git a/synth.metadata b/synth.metadata
index df2b53ad..6ccc8834 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -4,15 +4,15 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-iam.git",
-        "sha": "8e6faf1160d121b9b7949e8c8a21e7d312cd5fa0"
+        "sha": "4a64f7fb47f860e06bd4b23045f22a37b8d4d09b"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "0e915217fb5261c1e57bfaf0e16ee5c7feaaba89",
-        "internalRef": "361377784"
+        "sha": "d2977af9e9f1fc0c9dc8368352daa032471f3c63",
+        "internalRef": "403132955"
       }
     },
     {