Java hangs when trying to close a ProcessBuilder OutputStream

Question

I have the following Java code to start a ProcessBuilder, open an OutputStream, have the process write a string to an OutputStream, and then close the OutputStream. The who

Answer 1

Do you have anything reading from stdout/stderr of the process ?

It's quite likely the process tries to output something, but gets blocked since noone is reading the output. Meaning your out.flush() or out.close() blocks as the process can't get around to process the input since its blocked doing output.