How to Run Commands through a already running Java?

Question

I was wondering if it was possible to execute commands from PHP to a Java prompt which is already running?

I have tried the solution listed here: How to run a shell command through PHP code?

and this provided no functionality

Let me explain

The java is running on one screen of the linux server

sudo apt-get install screen

and running the .jar file through the command line.

I am then running a webserver, which will have an admin accessibility to restricted areas, which will contain scrips to run specific commands through that already running .jar file?

Answer 1

You can implement some kind of IPC. The java file listens to a port and receives the commands. Or you can write the commands in a specific file which the java programm reads. I think under linux you can also use shared memory: http://www.php.net/manual/en/book.shmop.php

Answer 2

It is possible by sending the command to the screen session. I used this for a minecraft server once.

screen -S <sessionname> -X stuff "<command>\r"

This would (IIRC) provide the same output as if you where inside the screen, typed the command and pressed enter. I hope this was what you wanted.