ConsoleAppender is blocking

Question

I am not sure what is happening here. I am starting a RMI server in a separate JVM. While connecting to the instance calling the remote method, the method get stuck after a very short time. The execution continues as soon as I shutdown the client process.

What am I doing wrong?

class Client

...
//name some kind of name
String name= "HelloService";

//libname points to a runnable jar with the server class as main class
ProcessBuilder jvm= new ProcessBuilder(javaPath, "-jar", libname, "-n", name);
jvm.start();

//Waiting for RMI server to start
try { Thread.sleep(10000); } catch ...

try {

   Registry registry= LocateRegistry.getRegistry(1199);

   //String as input and String as output
   IRemoteService<String, String> service= (IRemoteService<String, String>) registry.lookup(name)

   String returnVal= service.execute("SomeValue");
   return returnVal;
} catch ...

Following by the server code snip. The server code is packed in a runnable jar with itself as the MainClass.

class Server implements IRemoteService<String, String>

   //Is not returning a value, due the fact that I liked to examine the behaviour of
   //this method. Doing this by running an infinite loop.
   public String execute(String str) {
       log.info("Running doExectue from "+getClass().getSimpleName());

    int i=0;
    while(true) {
        i++;
        log.info(String.valueOf(i));
    }
   }


  protected static void register(String name, IRemoteService service) {

    try {
      IRemoteService rsStub= (IRemoteService) UnicastRemoteObject.exportObject(service,0);
      Registry registry= LocateRegistry.getRegistry(1199);
      try {
          registry.bind(name, rsStub);
      } catch (ConnectException ce) {
            registry= LocateRegistry.createRegistry(1199);
            registry.bind(name, rsStub);
      }
    } catch ...
  }   

   public static void main(String[] args) {            

    String rmiName= args[1];

    IRemoteService<String, String> service= (IRemoteService<String, String>) new Server();
    register(rmiName, service);    

   }

Now if I start the client the log file displayes 36 runs of the loop in method "execute". Than it stops. There is no other client getting this object or calling this method too.

It starts a again and is running forever as soon as I killed the Client process.

For me it looks like that the client is blocking the execution of the remote server methods. But I have no clue how to overcome this situation.

Thanks for any help in advance,

Danny

score 0 · Answer 1 · answered May 23 '14 at 12:00

0

What you describe is impossible. The client can't block the server while the server is executing a remote method. Find another explanation.

answered May 23 '14 at 12:00

user207421

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score 0 · Accepted Answer · answered May 26 '14 at 06:23

thanks for your support. You are right a RMI client can't block the server. So I was really confused. But I found the failure.

It about the process is writing to the console. As soon as the buffer is full the process is stopping to wait for someone collecting the output.

After I removed the ConsoleAppender from the log configuration the job runs as expected.

ConsoleAppender is blocking

2 Answers2