core: promote experimental methods in MethodDescriptor

core/src/main/java/io/grpc/MethodDescriptor.java

@@ -31,6 +31,8 @@
 
 package io.grpc;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import com.google.common.base.Preconditions;
 
 import java.io.InputStream;
@@ -197,7 +199,6 @@ public class MethodDescriptor<ReqT, RespT> {
    * @param requestMarshaller the marshaller used to encode and decode requests
    * @param responseMarshaller the marshaller used to encode and decode responses
    */
-  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1774")
   public static <RequestT, ResponseT> MethodDescriptor<RequestT, ResponseT> create(
       MethodType type, String fullMethodName,
       Marshaller<RequestT> requestMarshaller,
@@ -345,9 +346,10 @@ public class MethodDescriptor<ReqT, RespT> {
    * @param fullServiceName the fully qualified service name that is prefixed with the package name
    * @param methodName the short method name
    */
-  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1774")
   public static String generateFullMethodName(String fullServiceName, String methodName) {
-    return fullServiceName + "/" + methodName;
+    return checkNotNull(fullServiceName, "fullServiceName")
+        + "/"
+        + checkNotNull(methodName, "methodName");
   }
 
   /**
@@ -355,10 +357,9 @@ public class MethodDescriptor<ReqT, RespT> {
    * {@code null} if the input is malformed, but you cannot rely on it for the validity of the
    * input.
    */
-  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1774")
   @Nullable
   public static String extractFullServiceName(String fullMethodName) {
-    int index = fullMethodName.lastIndexOf('/');
+    int index = checkNotNull(fullMethodName, "fullMethodName").lastIndexOf('/');
     if (index == -1) {
       return null;
     }