Attempting to execute .jar file using python

Question

I have a .jar file that I need to execute via Python.

My current code is

import subprocess
subprocess.check_output(['java', '-jar', 'StatsCalc.jar'])

I printed out the error message:

Traceback (most recent call last):
File "C:\Users\ali\Documents\Java Stuff\RedditFitnessCalc\out\artifacts\RedditFitnessCalc_jar\pythonBotScript.py", line 6, in <module>
p = subprocess.check_output(['java', '-jar', 'RedditFitnessCalc.jar'])
File "C:\Program Files (x86)\Python 3\lib\subprocess.py", line 620, in check_output
raise CalledProcessError(retcode, process.args, output=output)
subprocess.CalledProcessError: Command '['java', '-jar', 'RedditFitnessCalc.jar']' returned non-zero exit status 2

When I run it, a window pops up and disappears instantly. It is a java program that has a GUI. I tried running it directly and with a batch file and both work fine.

Try using `check_output` instead of `call` and post the result. — domoarigato, May 29 '16 at 17:38
I'm assuming you have looked at http://stackoverflow.com/questions/7372592/python-how-can-execute-a-jar-file-through-a-python-script and the three other questions it links to. — Tadhg McDonald-Jensen, May 29 '16 at 17:46
@TadhgMcDonald-Jensen Yes, I did and I tried all of the solutions but to no avail. Apoligies if it seems like a duplicated but I edited it to include the error. — RedCardOP, May 29 '16 at 17:57
@domoarrigato As you said, I have posted the error message, though I cant seem to decipher what is the problem. — RedCardOP, May 29 '16 at 18:00
@TadhgMcDonald-Jensen Yes! It worked and the GUI shows up. If you don't mind posting it as the answer. Thank you! — RedCardOP, May 29 '16 at 18:05

score 2 · Accepted Answer · answered May 29 '16 at 18:11

One thing that frequently works is using shell=True option on the subprocess, this executes the command as if it was done in a shell (batch file or command prompt)

So using:

import subprocess
subprocess.call(['java', '-jar', 'StatsCalc.jar'],shell=True)

Should work for you, but please read the Security Considerations section of the subprocess's documentation before relying too heavily on this.

Usually the reason it does not work without shell is because it cannot find the command java without using the full path, so if you know the full path of the java executable that would be preferable to using shell=True

import subprocess
subprocess.call(['path/to/java', '-jar', 'StatsCalc.jar'])

I don't know the exact details on the difference between these two but

Attempting to execute .jar file using python

1 Answers1