Executing a different Jar file from another java program

Question

As a part of my program, I have a connections manager that receives a connection from a client, and then gives the client a port number and a password to use to connect. A

Answer 1

I have suceessfully tested the scenario and I can execute the jar file with in java programme (without setting the classpath).

Can you make sure that you have added Manifest file in the jar which has Main-Class attribute.

My steps and output:

1. Created Mainfest file with the following line: Main-Class: com.test.TestJSSJar
2. Created Test Java program:

package com.test;

public class TestJSSJar extends Object {

    public static void main(String args[]) {
        System.out.println("Hi! I'm in the jar");
        System.out.println("Arg:" + args[0]);
    }
}

3.Package the jar (moved to temp folder): jar cvfm jss.jar manifest.txt com

4.Write test program:

import java.io.BufferedInputStream;
import java.io.IOException;

public class TestJSS extends Object {

    static int i = 0;

    public static void main(String args[]) throws IOException, InterruptedException {
        System.out.println("Calling jar");
        Process p = Runtime.getRuntime().exec("java -jar /temp/jss.jar arg1 arg2");
        BufferedInputStream bis = new BufferedInputStream(p.getInputStream());
        synchronized (p) {
            p.waitFor();
        }
        System.out.println(p.exitValue());
        int b=0;
        while((b=bis.read()) >0){

            System.out.print((char)b);    
        }        
        System.out.println("");
        System.out.println("Called jar");
    }
}

5.Output

Calling jar
0
Hi! I'm in the jar
Arg:arg1

Called jar

Answer 2

Include jar in the classpath and call the main method of the Main-class of the jar from your main.

Suppose Main-class of CytoscapeInterface.jar is JarMain.class (You can look it up in META-INF of CytoscapeInterface.jar), then from your program, call it like this:

JarMain.main(new String[]{"arg1", "arg2"});

You can also call it from a new Thread so that you can continue with your program.

        new Thread(
        new Runnable() {
            public void run() {
                try {
                    JarMain.main(new String[]{"arg1", "arg2"});
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();