Create a childprocess and make it run a function or class method

Question

I come from a very C background and am totally new to Java. What I want to do is something like fork() in C. I have looked at ProcessBuilder, but all examples seem to spawn an external process as in the following example:

Process p = new ProcessBuilder("/bin/chmod", "777", path).start();
p.waitFor();

I want the new child process to start executing a new function, or a class method.

What I want to do should behave something like:

Process p = new ProcessBuilder(<CLASS_METHOD>).start();
p.waitFor();

The parent process executes the next line (the line containing waitFor()) where as the child process begins executing the given <CLASS_METHOD>.

How can I get this done?

Additional question: Is there any way I can get a handler to SIGCHLD? I want to create a new child-process when one of the child processes die.

@RobbyCornelissen I do not want threads. I want separate processes. — Arjun Sreedharan, Oct 06 '16 at 03:55
Possible related question: http://stackoverflow.com/questions/26319804/adapting-c-fork-code-to-a-java-program — Nick Bell, Oct 06 '16 at 04:18

score 1 · Answer 1 · answered Oct 06 '16 at 15:27

1

Why can't you just create a new java process using the process builder? Something like following.

Process p = new ProcessBuilder("/bin/java /tmp/Main.class").start();
p.waitFor();

if you don't want to hard code the class path, you can do the following to get the path.

String path = Main.class.getProtectionDomain().getCodeSource().getLocation().getPath();

answered Oct 06 '16 at 15:27

Anand J

18
2

My question is - I do not want to run a command via a string. I want the control to go to a function or block of code for the child process. – Arjun Sreedharan Oct 06 '16 at 19:28
FTR: Upvoted. It seems there's no solution other than via command. Thanks. – Arjun Sreedharan Oct 07 '16 at 22:50

Create a childprocess and make it run a function or class method

1 Answers1