This seems to be fixed.

```
#!/usr/bin/python

import subprocess as sp
import threading
import os

def netbeans_start_lock(sh="sh"):
    threads = []
    def __thread__():
        sp.check_call([sh, os.path.join(os.environ["HOME"], "netbeans-8.2", "bin", "netbeans")])
    for i in range(0,50):
        thread = threading.Thread(target=__thread__)
        thread.start()
        threads.append(thread)
    while len(threads) > 0:
        thread = threads.pop()
        thread.join()

if __name__ == "__main__":
    netbeans_start_lock()
```

only starts one instance.