local example fails with "java.lang.NoClassDefFoundError: net/devh/boot/grpc/examples/lib/HelloReply$Builder"

[oneiros-de]

The context

Run the local example as described on https://github.com/yidongnan/grpc-spring-boot-starter/tree/master/examples#local-mode

The bug

Both services start, but upon calling the webpage, the server throws an
java.lang.NoClassDefFoundError: net/devh/boot/grpc/examples/lib/HelloReply$Builder

Stacktrace and logs

> Task :examples:local-grpc-server:bootRun

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.6.2)

2022-03-10 14:43:53.671  INFO 411577 --- [           main] n.d.b.g.e.l.s.LocalGrpcServerApplication : Starting LocalGrpcServerApplication using Java 1.8.0_312 on dtm2573lapli with PID 411577 (/home/martinsc/java/github/grpc-spring-boot-starter/examples/local-grpc-server/build/classes/java/main started by martinsc in /home/martinsc/java/github/grpc-spring-boot-starter/examples/local-grpc-server)
2022-03-10 14:43:53.679  INFO 411577 --- [           main] n.d.b.g.e.l.s.LocalGrpcServerApplication : No active profile set, falling back to default profiles: default
2022-03-10 14:43:55.949  INFO 411577 --- [           main] g.s.a.GrpcServerFactoryAutoConfiguration : Detected grpc-netty-shaded: Creating ShadedNettyGrpcServerFactory
2022-03-10 14:43:56.653  INFO 411577 --- [           main] n.d.b.g.s.s.AbstractGrpcServerFactory    : Registered gRPC service: Simple, bean: grpcServerService, class: net.devh.boot.grpc.examples.local.server.GrpcServerService
2022-03-10 14:43:56.654  INFO 411577 --- [           main] n.d.b.g.s.s.AbstractGrpcServerFactory    : Registered gRPC service: grpc.health.v1.Health, bean: grpcHealthService, class: io.grpc.protobuf.services.HealthServiceImpl
2022-03-10 14:43:56.654  INFO 411577 --- [           main] n.d.b.g.s.s.AbstractGrpcServerFactory    : Registered gRPC service: grpc.reflection.v1alpha.ServerReflection, bean: protoReflectionService, class: io.grpc.protobuf.services.ProtoReflectionService
2022-03-10 14:43:57.330  INFO 411577 --- [           main] n.d.b.g.s.s.GrpcServerLifecycle          : gRPC Server started, listening on address: *, port: 9898
2022-03-10 14:43:57.392  INFO 411577 --- [           main] n.d.b.g.e.l.s.LocalGrpcServerApplication : Started LocalGrpcServerApplication in 5.268 seconds (JVM running for 6.702)
2022-03-10 14:49:52.489  INFO 411577 --- [ault-executor-0] n.d.b.g.e.l.server.LogGrpcInterceptor    : Simple/SayHello
Exception in thread "grpc-default-executor-0" java.lang.NoClassDefFoundError: net/devh/boot/grpc/examples/lib/HelloReply$Builder
        at net.devh.boot.grpc.examples.lib.HelloReply.toBuilder(HelloReply.java:276)
        at net.devh.boot.grpc.examples.lib.HelloReply.newBuilder(HelloReply.java:269)
        at net.devh.boot.grpc.examples.local.server.GrpcServerService.sayHello(GrpcServerService.java:36)
        at net.devh.boot.grpc.examples.lib.SimpleGrpc$MethodHandlers.invoke(SimpleGrpc.java:232)
        at io.grpc.stub.ServerCalls$UnaryServerCallHandler$UnaryServerCallListener.onHalfClose(ServerCalls.java:182)
        at io.grpc.PartialForwardingServerCallListener.onHalfClose(PartialForwardingServerCallListener.java:35)
        at io.grpc.ForwardingServerCallListener.onHalfClose(ForwardingServerCallListener.java:23)
        at io.grpc.ForwardingServerCallListener$SimpleForwardingServerCallListener.onHalfClose(ForwardingServerCallListener.java:40)
        at io.grpc.Contexts$ContextualizedServerCallListener.onHalfClose(Contexts.java:86)
        at io.grpc.internal.ServerCallImpl$ServerStreamListenerImpl.halfClosed(ServerCallImpl.java:340)
        at io.grpc.internal.ServerImpl$JumpToApplicationThreadServerStreamListener$1HalfClosed.runInContext(ServerImpl.java:866)
        at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
        at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: net.devh.boot.grpc.examples.lib.HelloReply$Builder
        at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
        ... 16 more

Steps to Reproduce

Steps to reproduce the behavior:

1. Checkout the project from github
2. Run the steps in "Local Setup"

The application's environment

Which versions do you use?

• Spring (boot): as in the repo
• grpc-java: as in the repo
• grpc-spring-boot-starter: as in the repo
• java: version + architecture (64bit?)

> java -version
openjdk version "11.0.14" 2022-01-18
OpenJDK Runtime Environment (build 11.0.14+9-Ubuntu-0ubuntu2.20.04)
OpenJDK 64-Bit Server VM (build 11.0.14+9-Ubuntu-0ubuntu2.20.04, mixed mode, sharing)

• Other relevant libraries...

Additional context

• Did it ever work before? No

[ST-DDT]

This might be caused by some gradle shenanigans.

You can run the examples if you duplicate the repo and run the server in the other copy.

Or by using these commands (from our example test script):
https://github.com/yidongnan/grpc-spring-boot-starter/blob/0668194d06abf43c625da5bb41036eb42c4cb166/testExamples.sh#L19-L32

./gradlew clean
./gradlew build
./gradlew :example:local-grpc-server:bootRun -x jar -x classes &
./gradlew :example:local-grpc-client:bootRun -x jar -x classes &

I will update the documentation to account for this.

[oneiros-de]

Copying the repo worked; thanks.