Server server = ServerBuilder.forPort(50051) .addService(new MyService()) .build(); ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 50051) .build(); Server server = ServerBuilder.forPort(50051) .addService(new MyService()) .build(); ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 50051) .build(); public class AuthInterceptor implements ServerInterceptor { @Override public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall( ServerCall<ReqT, RespT> call, Metadata headers, ServerCallHandler<ReqT, RespT> next) { return next.startCall(call, headers); } } Server server = ServerBuilder.forPort(50051) .addService(ServerInterceptors.intercept(new MyService(), new AuthInterceptor())) .build(); proto syntax = "proto3"; package mypackage; message MyRequest { string data = 1 [(validate.rules) = {required: true}]; } service MyService { rpc MyMethod (MyRequest) returns (MyResponse) {} }