diff --git a/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/BenchmarkServiceGrpc.java b/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/BenchmarkServiceGrpc.java
index 54c14c257e..1da566775a 100644
--- a/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/BenchmarkServiceGrpc.java
+++ b/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/BenchmarkServiceGrpc.java
@@ -269,16 +269,22 @@ public class BenchmarkServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new BenchmarkServiceDescriptorSupplier(),
-          METHOD_UNARY_CALL,
-          METHOD_STREAMING_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (BenchmarkServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new BenchmarkServiceDescriptorSupplier(),
+              METHOD_UNARY_CALL,
+              METHOD_STREAMING_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/WorkerServiceGrpc.java b/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/WorkerServiceGrpc.java
index 4b7d264b2e..5e946bb992 100644
--- a/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/WorkerServiceGrpc.java
+++ b/benchmarks/src/generated/main/grpc/io/grpc/benchmarks/proto/WorkerServiceGrpc.java
@@ -387,18 +387,24 @@ public class WorkerServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new WorkerServiceDescriptorSupplier(),
-          METHOD_RUN_SERVER,
-          METHOD_RUN_CLIENT,
-          METHOD_CORE_COUNT,
-          METHOD_QUIT_WORKER);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (WorkerServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new WorkerServiceDescriptorSupplier(),
+              METHOD_RUN_SERVER,
+              METHOD_RUN_CLIENT,
+              METHOD_CORE_COUNT,
+              METHOD_QUIT_WORKER);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/compiler/src/java_plugin/cpp/java_generator.cpp b/compiler/src/java_plugin/cpp/java_generator.cpp
index 74dfd3cf0c..6cfb97a43d 100644
--- a/compiler/src/java_plugin/cpp/java_generator.cpp
+++ b/compiler/src/java_plugin/cpp/java_generator.cpp
@@ -905,44 +905,40 @@ static void PrintGetServiceDescriptorMethod(const ServiceDescriptor* service,
     p->Print(*vars, "}\n");
     p->Outdent();
     p->Print(*vars, "}\n\n");
-
-    p->Print(
-            *vars,
-            "private static $ServiceDescriptor$ serviceDescriptor;\n\n");
-
-    p->Print(
-        *vars,
-        "public static synchronized $ServiceDescriptor$ getServiceDescriptor() {\n");
-    p->Indent();
-    p->Print("if (serviceDescriptor == null) {\n");
-    p->Indent();
-    p->Print(
-        *vars,
-        "serviceDescriptor = new $ServiceDescriptor$(SERVICE_NAME,\n");
-    p->Indent();
-    p->Indent();
-    p->Print(
-        *vars,
-        "new $proto_descriptor_supplier$()");
-    p->Outdent();
-    p->Outdent();
-  } else {
-    p->Print(
-      *vars,
-      "private static $ServiceDescriptor$ serviceDescriptor;\n\n");
-    p->Print(
-        *vars,
-        "public static synchronized $ServiceDescriptor$ getServiceDescriptor() {\n");
-    p->Indent();
-    p->Print("if (serviceDescriptor == null) {\n");
-    p->Indent();
-    p->Print(
-        *vars,
-        "serviceDescriptor = new $ServiceDescriptor$(SERVICE_NAME");
   }
 
+  p->Print(
+      *vars,
+      "private static volatile $ServiceDescriptor$ serviceDescriptor;\n\n");
+
+  p->Print(
+      *vars,
+      "public static $ServiceDescriptor$ getServiceDescriptor() {\n");
+  p->Indent();
+  p->Print(
+      *vars,
+      "$ServiceDescriptor$ result = serviceDescriptor;\n");
+  p->Print("if (result == null) {\n");
+  p->Indent();
+  p->Print(
+      *vars,
+      "synchronized ($service_class_name$.class) {\n");
+  p->Indent();
+  p->Print("result = serviceDescriptor;\n");
+  p->Print("if (result == null) {\n");
+  p->Indent();
+
+  p->Print(
+      *vars,
+      "serviceDescriptor = result = new $ServiceDescriptor$(\n");
   p->Indent();
   p->Indent();
+  p->Print("SERVICE_NAME");
+  if (flavor == ProtoFlavor::NORMAL) {
+    p->Print(
+        *vars,
+        ",\nnew $proto_descriptor_supplier$()");
+  }
   for (int i = 0; i < service->method_count(); ++i) {
     const MethodDescriptor* method = service->method(i);
     (*vars)["method_field_name"] = MethodPropertiesFieldName(method);
@@ -951,8 +947,14 @@ static void PrintGetServiceDescriptorMethod(const ServiceDescriptor* service,
   p->Print(");\n");
   p->Outdent();
   p->Outdent();
+
   p->Outdent();
-  p->Print("}\n\nreturn serviceDescriptor;\n");
+  p->Print("}\n");
+  p->Outdent();
+  p->Print("}\n");
+  p->Outdent();
+  p->Print("}\n");
+  p->Print("return result;\n");
   p->Outdent();
   p->Print("}\n");
 }
diff --git a/compiler/src/test/golden/TestService.java.txt b/compiler/src/test/golden/TestService.java.txt
index 61317e4b6b..86bc9875ba 100644
--- a/compiler/src/test/golden/TestService.java.txt
+++ b/compiler/src/test/golden/TestService.java.txt
@@ -432,19 +432,25 @@ public class TestServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new TestServiceDescriptorSupplier(),
-          METHOD_UNARY_CALL,
-          METHOD_STREAMING_OUTPUT_CALL,
-          METHOD_STREAMING_INPUT_CALL,
-          METHOD_FULL_BIDI_CALL,
-          METHOD_HALF_BIDI_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (TestServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new TestServiceDescriptorSupplier(),
+              METHOD_UNARY_CALL,
+              METHOD_STREAMING_OUTPUT_CALL,
+              METHOD_STREAMING_INPUT_CALL,
+              METHOD_FULL_BIDI_CALL,
+              METHOD_HALF_BIDI_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/compiler/src/testLite/golden/TestService.java.txt b/compiler/src/testLite/golden/TestService.java.txt
index 753bf29848..6720b78569 100644
--- a/compiler/src/testLite/golden/TestService.java.txt
+++ b/compiler/src/testLite/golden/TestService.java.txt
@@ -425,18 +425,24 @@ public class TestServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          METHOD_UNARY_CALL,
-          METHOD_STREAMING_OUTPUT_CALL,
-          METHOD_STREAMING_INPUT_CALL,
-          METHOD_FULL_BIDI_CALL,
-          METHOD_HALF_BIDI_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (TestServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              METHOD_UNARY_CALL,
+              METHOD_STREAMING_OUTPUT_CALL,
+              METHOD_STREAMING_INPUT_CALL,
+              METHOD_FULL_BIDI_CALL,
+              METHOD_HALF_BIDI_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/compiler/src/testNano/golden/TestService.java.txt b/compiler/src/testNano/golden/TestService.java.txt
index 6d3ca209c0..31701a59d5 100644
--- a/compiler/src/testNano/golden/TestService.java.txt
+++ b/compiler/src/testNano/golden/TestService.java.txt
@@ -503,18 +503,24 @@ public class TestServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          METHOD_UNARY_CALL,
-          METHOD_STREAMING_OUTPUT_CALL,
-          METHOD_STREAMING_INPUT_CALL,
-          METHOD_FULL_BIDI_CALL,
-          METHOD_HALF_BIDI_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (TestServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              METHOD_UNARY_CALL,
+              METHOD_STREAMING_OUTPUT_CALL,
+              METHOD_STREAMING_INPUT_CALL,
+              METHOD_FULL_BIDI_CALL,
+              METHOD_HALF_BIDI_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java b/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java
index 3cdd99336a..196b3f19a6 100644
--- a/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java
+++ b/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java
@@ -200,15 +200,21 @@ public class LoadBalancerGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new LoadBalancerDescriptorSupplier(),
-          METHOD_BALANCE_LOAD);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (LoadBalancerGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new LoadBalancerDescriptorSupplier(),
+              METHOD_BALANCE_LOAD);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java b/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
index 6bf9313ce5..7d7c66a4fb 100644
--- a/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
+++ b/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
@@ -210,15 +210,21 @@ public class HealthGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new HealthDescriptorSupplier(),
-          METHOD_CHECK);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (HealthGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new HealthDescriptorSupplier(),
+              METHOD_CHECK);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/services/src/generated/main/grpc/io/grpc/reflection/v1alpha/ServerReflectionGrpc.java b/services/src/generated/main/grpc/io/grpc/reflection/v1alpha/ServerReflectionGrpc.java
index c622ab437f..5527379c62 100644
--- a/services/src/generated/main/grpc/io/grpc/reflection/v1alpha/ServerReflectionGrpc.java
+++ b/services/src/generated/main/grpc/io/grpc/reflection/v1alpha/ServerReflectionGrpc.java
@@ -202,15 +202,21 @@ public class ServerReflectionGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new ServerReflectionDescriptorSupplier(),
-          METHOD_SERVER_REFLECTION_INFO);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (ServerReflectionGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new ServerReflectionDescriptorSupplier(),
+              METHOD_SERVER_REFLECTION_INFO);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/services/src/generated/test/grpc/io/grpc/reflection/testing/DynamicServiceGrpc.java b/services/src/generated/test/grpc/io/grpc/reflection/testing/DynamicServiceGrpc.java
index e954845c6a..d329b6e56f 100644
--- a/services/src/generated/test/grpc/io/grpc/reflection/testing/DynamicServiceGrpc.java
+++ b/services/src/generated/test/grpc/io/grpc/reflection/testing/DynamicServiceGrpc.java
@@ -210,15 +210,21 @@ public class DynamicServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new DynamicServiceDescriptorSupplier(),
-          METHOD_METHOD);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (DynamicServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new DynamicServiceDescriptorSupplier(),
+              METHOD_METHOD);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/services/src/generated/test/grpc/io/grpc/reflection/testing/ReflectableServiceGrpc.java b/services/src/generated/test/grpc/io/grpc/reflection/testing/ReflectableServiceGrpc.java
index c6b8861c58..ac89434a69 100644
--- a/services/src/generated/test/grpc/io/grpc/reflection/testing/ReflectableServiceGrpc.java
+++ b/services/src/generated/test/grpc/io/grpc/reflection/testing/ReflectableServiceGrpc.java
@@ -210,15 +210,21 @@ public class ReflectableServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new ReflectableServiceDescriptorSupplier(),
-          METHOD_METHOD);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (ReflectableServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new ReflectableServiceDescriptorSupplier(),
+              METHOD_METHOD);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
index c5f86bd938..4ad608024d 100644
--- a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
+++ b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
@@ -278,16 +278,22 @@ public class MetricsServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new MetricsServiceDescriptorSupplier(),
-          METHOD_GET_ALL_GAUGES,
-          METHOD_GET_GAUGE);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (MetricsServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new MetricsServiceDescriptorSupplier(),
+              METHOD_GET_ALL_GAUGES,
+              METHOD_GET_GAUGE);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
index 15aa3885c8..a92abcae8a 100644
--- a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
+++ b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
@@ -276,16 +276,22 @@ public class ReconnectServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new ReconnectServiceDescriptorSupplier(),
-          METHOD_START,
-          METHOD_STOP);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (ReconnectServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new ReconnectServiceDescriptorSupplier(),
+              METHOD_START,
+              METHOD_STOP);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
index 42859d7199..4ebd5d96d9 100644
--- a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
+++ b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
@@ -563,21 +563,27 @@ public class TestServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new TestServiceDescriptorSupplier(),
-          METHOD_EMPTY_CALL,
-          METHOD_UNARY_CALL,
-          METHOD_STREAMING_OUTPUT_CALL,
-          METHOD_STREAMING_INPUT_CALL,
-          METHOD_FULL_DUPLEX_CALL,
-          METHOD_HALF_DUPLEX_CALL,
-          METHOD_UNIMPLEMENTED_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (TestServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new TestServiceDescriptorSupplier(),
+              METHOD_EMPTY_CALL,
+              METHOD_UNARY_CALL,
+              METHOD_STREAMING_OUTPUT_CALL,
+              METHOD_STREAMING_INPUT_CALL,
+              METHOD_FULL_DUPLEX_CALL,
+              METHOD_HALF_DUPLEX_CALL,
+              METHOD_UNIMPLEMENTED_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }
diff --git a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
index cbb09fd770..e6c6a987e9 100644
--- a/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
+++ b/testing-proto/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
@@ -242,15 +242,21 @@ public class UnimplementedServiceGrpc {
     }
   }
 
-  private static io.grpc.ServiceDescriptor serviceDescriptor;
+  private static volatile io.grpc.ServiceDescriptor serviceDescriptor;
 
-  public static synchronized io.grpc.ServiceDescriptor getServiceDescriptor() {
-    if (serviceDescriptor == null) {
-      serviceDescriptor = new io.grpc.ServiceDescriptor(SERVICE_NAME,
-          new UnimplementedServiceDescriptorSupplier(),
-          METHOD_UNIMPLEMENTED_CALL);
+  public static io.grpc.ServiceDescriptor getServiceDescriptor() {
+    io.grpc.ServiceDescriptor result = serviceDescriptor;
+    if (result == null) {
+      synchronized (UnimplementedServiceGrpc.class) {
+        result = serviceDescriptor;
+        if (result == null) {
+          serviceDescriptor = result = new io.grpc.ServiceDescriptor(
+              SERVICE_NAME,
+              new UnimplementedServiceDescriptorSupplier(),
+              METHOD_UNIMPLEMENTED_CALL);
+        }
+      }
     }
-
-    return serviceDescriptor;
+    return result;
   }
 }