How to handle starting of external processes with Runtime.exec() properly

Question

hi people,
you find a lot about starting external processes with the Runtime class in every forum.
-> that the stdout of the started processes has to be redirected and read
due to os buffer problems
-> that calling batches is done by starting the interpreter and the batch as parameter (cmd.exe, /bin/sh,..)
-> that the created process doesn't have an os environment
-> ...
but what if you don't know anything about the started process.
what if you only want only to start an external process. if you don't want to wait til waitfor() returns and if you don't read the streams of the created processes, the os stdout buffer will overflow immediately an the started process will be blocked.
you can read the stdout of the started process, but what if the process does print nothing to stdout, and your bufferreader.readLine() will block ?
you can do this (read buffer, waitFor()) in an separate thread, but the thread lives til the started process will finish, so maybe you got dozens of senseless thread ?
So, what is an effective and good way to start external programs/processes if you don't know about them.
so i would be grateful for an answer
regards
Alen

Answer 1

I realize that's a pat answer, but it's true. Spawing off another program without being able to predict its behavior is dangerous.
But anyway, as I understand it creating a new process is relatively expensive. The cost of creating new threads to read the process's I/O and later garbage collecting those threads when the process dies, probably isn't much of an additional burden.