Can one main thread call other main thread in java

Question

I am looking for some more knowledge about java main method public static void main(String[] args) .When JVM call main method it creates Main thread and the whole program is get executed in this Main thread until some user thread explicitly get started in its own stack.

My question is that is it possible to start main thread from some other main method?

Its better if someone can give me some reference about main thread.

@user1329572 That i know . can you please read my question again. — amicngh, Jun 08 '12 at 12:08
Do you want to spawn a whole new JVM? Or just call the main method from a thread that is not the Main thread? — serg10, Jun 08 '12 at 12:14

score 8 · Accepted Answer · answered Jun 08 '12 at 12:07

8

The main thread is just a concept, it's a name for the thread that starts your app, this thread is not special in any way (other than not being a daemon thread) so you can easily create new threads that are not daemons also and call another main method on them.

There isn't anything special about being the main thread, it's just the first thread to be started.

answered Jun 08 '12 at 12:07

Maurício Linhares

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So this thread is started by JVM .But let say my application has two main methods and i want to call one method from other . – amicngh Jun 08 '12 at 12:13
2

You just call it **SomeClass.main( args )**, nothing special about it. The main method is also **just a method**, there isn't anything special about it either. – Maurício Linhares Jun 08 '12 at 12:17
but it will run in same stack means it will not create one more main thread – amicngh Jun 08 '12 at 12:18
So you should create a new thread and call it on this new thread. – Maurício Linhares Jun 08 '12 at 12:19

score 0 · Answer 2 · answered Jun 08 '12 at 12:08

0

As far as my knowledgee, main thread is started by the JVM and the other threads started by the user are the sub-thread of the main thread in that thread group.

answered Jun 08 '12 at 12:08

Chandra Sekhar

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score 0 · Answer 3 · edited May 23 '17 at 12:21

class FirstApp {
    public static void main(String[] args) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                SecondApp.main(args);
            }
        }).start();

Starts a new thread and calls the main method of another application. Works fine. But they run both in the same process.

However, if you want to do it as if it was executed from command line (in another (separate) process), you can also do something like this:

import java.io.File;
import java.io.IOException;
import java.lang.management.ManagementFactory;

public class Main {
    public static void main(String[] args) throws IOException, InterruptedException {
        StringBuilder cmd = new StringBuilder();
        cmd.append(System.getProperty("java.home") + File.separator + "bin" + File.separator + "java ");
        for (String jvmArg : ManagementFactory.getRuntimeMXBean().getInputArguments()) {
            cmd.append(jvmArg + " ");
        }
        cmd.append("-cp ").append(ManagementFactory.getRuntimeMXBean().getClassPath()).append(" ");
        cmd.append(Main2.class.getName()).append(" "); // Main2 is the main class of the second application
        for (String arg : args) {
            cmd.append(arg).append(" ");
        }
        Runtime.getRuntime().exec(cmd.toString());
       // continue with your normal app code here
    }
}

I took the second code mostly from How can I restart a Java application?

Can one main thread call other main thread in java

3 Answers3