The right way to kill a process in Java

Question

What's the best way to kill a process in Java ?

Get the PID and then killing it with Runtime.exec() ?

Use destroyForcibly() ?

What's the difference between these two methods, and is there any others solutions ?

Answer 1

If the process you want to kill has been started by your application

Then you probably have a reference to it (ProcessBuilder.start() or Runtime.exec() both return a reference). In this case, you can simply call p.destroy(). I think this is the cleanest way (but be careful: sub-processes started by p may stay alive, check Process.destroy does not kill multiple child processes for more info).

The destroyForcibly should only be used if destroy() failed after a certain timeout. In a nutshell

1. terminate process with destroy()
2. allow process to exit gracefully with reasonable timeout
3. kill it with destroyForcibly() if process is still alive

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If the process you want to kill is external

Then you don't have much choice: you need to pass through the OS API (Runtime.exec). On Windows, the program to call will be taskkill.exe, while on Mac and Linux you can try kill.

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Have a look at Support for Process.destroyForcibly() and .isAlive() from Java 8 and Killing a process using Java and Code a Simple Java App to Kill Any Process After a Specified Time for more info.