Distribute a Java application over several JVMs

This library provides a simple way for distributing Java applications over several nodes.

Each node must run a generic application-agnostic daemon (written itself in Java). This daemon is launched by:

java -cp ant.jar:remotejvm.jar com.remotejvm.Node

The JVMs do not share their memory but they can communicate and exchange data.

The Java application itself is automagically distributed to nodes.

You can browse the Javadoc online. There are only three public classes to do all the job.

Usage

Here is a simple example

public class Demo { 
    static public interface Worker extends Serializable { 
        // Just compute the sum of two integers 
        public Integer add(Integer a, Integer b); 
    } 
    static public class WorkerImpl implements Worker { 
        public Integer add(Integer a, Integer b) { 
            // This will be printed in the JVM that runs the method 
            System.out.println("Computing sum " + a + " and " + b); 
            return a + b; 
        } 
    } 
    public static void main(String[] args) throws RemoteException { 
        // This computation is done locally 
        Worker local = new WorkerImpl(); 
        System.out.println("local=" + local.add(3, 4)); 

        // The remote JVM runs on the local host 
        RemoteJVM remoteJVM = RemoteJVMUtils.create("127.0.0.1"); 

        // This computation is done on the remote JVM. 
        // So all arguments and result must be Serializable 
        Worker remote = (Worker) remoteJVM.transfert(local); 
        System.out.println("remote=" + remote.add(5, 6)); 
    } 
}

In the current example, the call to the remote Worker is done synchronously. Using Future interface, we have ideas for providing asynchronous calls.

Test yourself!

Just download both ant.jar and remotejvm.jar files. Depending on your system, download run_node.bat/.sh and run_demo.bat/.sh

1. Put all files in the same directory.
2. Double-click or launch run_node : this will launch the daemon.
3. Double-click or launch run_demo in another window : this will launch the Java code listed below.

You will see that computations is done in both JVM, but that results are printed in the second window.

A folder named 11001 will be created : this is where classes are deserialized for the daemon (because in real world, run_node and run_demo should be launched on different machines.

By the way, you can edit run_demo file and change the IP address 127.0.0.1 to a real IP of yours, and make a test on two differents machines.

Notes about ANT

ANT is only used to launch JVM : this is the best portable way to launch JVM from Java.