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 0ab1979..8883137 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
@@ -67,6 +67,7 @@
         io.grpc.stub.StreamObserver<io.grpc.benchmarks.proto.Messages.SimpleResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractBenchmarkService implements BenchmarkService, io.grpc.BindableService {
 
     @java.lang.Override
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 9fb1c08..52d0193 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
@@ -91,6 +91,7 @@
         io.grpc.stub.StreamObserver<io.grpc.benchmarks.proto.Control.Void> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractWorkerService implements WorkerService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/compiler/src/java_plugin/cpp/java_generator.cpp b/compiler/src/java_plugin/cpp/java_generator.cpp
index 54c6067..8a65b06 100644
--- a/compiler/src/java_plugin/cpp/java_generator.cpp
+++ b/compiler/src/java_plugin/cpp/java_generator.cpp
@@ -297,6 +297,7 @@
   if (abstract) {
     p->Print(
         *vars,
+        "@$ExperimentalApi$\n"
         "public static abstract class $abstract_name$ implements $service_name$, "
         "$BindableService$ {\n");
   } else if (!impl) {
diff --git a/compiler/src/test/golden/TestService.java.txt b/compiler/src/test/golden/TestService.java.txt
index ac6db78..57691bf 100644
--- a/compiler/src/test/golden/TestService.java.txt
+++ b/compiler/src/test/golden/TestService.java.txt
@@ -103,6 +103,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.Test.StreamingOutputCallResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/compiler/src/testLite/golden/TestService.java.txt b/compiler/src/testLite/golden/TestService.java.txt
index cb76da8..31002c9 100644
--- a/compiler/src/testLite/golden/TestService.java.txt
+++ b/compiler/src/testLite/golden/TestService.java.txt
@@ -103,6 +103,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.Test.StreamingOutputCallResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/compiler/src/testNano/golden/TestService.java.txt b/compiler/src/testNano/golden/TestService.java.txt
index ccd028e..1f2c91c 100644
--- a/compiler/src/testNano/golden/TestService.java.txt
+++ b/compiler/src/testNano/golden/TestService.java.txt
@@ -181,6 +181,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.nano.Test.StreamingOutputCallResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/examples/src/generated/main/grpc/io/grpc/examples/helloworld/GreeterGrpc.java b/examples/src/generated/main/grpc/io/grpc/examples/helloworld/GreeterGrpc.java
index 91631c2..d6f69dd 100644
--- a/examples/src/generated/main/grpc/io/grpc/examples/helloworld/GreeterGrpc.java
+++ b/examples/src/generated/main/grpc/io/grpc/examples/helloworld/GreeterGrpc.java
@@ -55,6 +55,7 @@
         io.grpc.stub.StreamObserver<io.grpc.examples.helloworld.HelloReply> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractGreeter implements Greeter, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/examples/src/generated/main/grpc/io/grpc/examples/routeguide/RouteGuideGrpc.java b/examples/src/generated/main/grpc/io/grpc/examples/routeguide/RouteGuideGrpc.java
index 8f4e473..d7dcdac 100644
--- a/examples/src/generated/main/grpc/io/grpc/examples/routeguide/RouteGuideGrpc.java
+++ b/examples/src/generated/main/grpc/io/grpc/examples/routeguide/RouteGuideGrpc.java
@@ -91,6 +91,7 @@
         io.grpc.stub.StreamObserver<io.grpc.examples.routeguide.RouteNote> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractRouteGuide implements RouteGuide, io.grpc.BindableService {
 
     @java.lang.Override
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 a91bb7e..1bd73a0 100644
--- a/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java
+++ b/grpclb/src/generated/main/grpc/io/grpc/grpclb/LoadBalancerGrpc.java
@@ -55,6 +55,7 @@
         io.grpc.stub.StreamObserver<io.grpc.grpclb.LoadBalanceResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractLoadBalancer implements LoadBalancer, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
index 49bd423..5685594 100644
--- a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
+++ b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/MetricsServiceGrpc.java
@@ -67,6 +67,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.Metrics.GaugeResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractMetricsService implements MetricsService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
index 64473f7..77f0d0b 100644
--- a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
+++ b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/ReconnectServiceGrpc.java
@@ -67,6 +67,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.Messages.ReconnectInfo> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractReconnectService implements ReconnectService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
index a3ccda4..b633b78 100644
--- a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
+++ b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/TestServiceGrpc.java
@@ -115,6 +115,7 @@
         io.grpc.stub.StreamObserver<io.grpc.testing.integration.Messages.StreamingOutputCallResponse> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
 
     @java.lang.Override
diff --git a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
index 0924a06..653301f 100644
--- a/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
+++ b/interop-testing/src/generated/main/grpc/io/grpc/testing/integration/UnimplementedServiceGrpc.java
@@ -55,6 +55,7 @@
         io.grpc.stub.StreamObserver<com.google.protobuf.EmptyProtos.Empty> responseObserver);
   }
 
+  @io.grpc.ExperimentalApi
   public static abstract class AbstractUnimplementedService implements UnimplementedService, io.grpc.BindableService {
 
     @java.lang.Override