what is the best way to start a asynchronous java process from j2ee application

Question

I am working on an j2ee application from where i need to initiate a another java process which might run for around 10 min. As UI will timeout, i have to initiate this process in asynchronous manner. I cannot use threads as i have to reuse existing code and will land up in synchronizing issues. So, please advice me on the best way to start the new asynchronous process?

Answer 1

Recently, I had to start a java process from a j2ee application.

I spwaned a new JVM and gave it all necessary (classpatch, Main class, jvm arguments, program arguments ...) for running the process.

How to spawn a JVM method?

public static Process createProcess(final String optionsAsString, final String workingDir, final String mainClass, final String[] arguments) throws IOException {
    String jvm = System.getProperty("java.home") + File.separator + "bin" + File.separator + "java";

    String[] options = optionsAsString.split(" ");
    List<String> command = new ArrayList<String>();
    command.add(jvm);
    command.addAll(Arrays.asList(options));
    command.add(mainClass);
    command.addAll(Arrays.asList(arguments));

    //System.out.println(command);

    ProcessBuilder processBuilder = new ProcessBuilder(command);
    processBuilder.directory(new File(workingDir));

    return processBuilder.start();
}

Sample usage

public static void makeItRun() {
   try {
      // Start JVM
      String classPath = buildClassPath();
      String workingDir = getSuitableWorkingDir();//or just "."
      Process java = createProcess("-cp \"" + classPath + "\"", workingDir, my.package.APP.class.getCanonicalName(), "-the -options -of -my -APP");

      // Communicate with your APP here ...

      // Stop JVM
      java.destroy();
   } catch(Throwable t) {
      t.printStackTrace();
   }
}