Java process.getInputStream() has nothing to read, deadlocks child

Answer 1

You need to use a threadsafe data structure; I don't think LinkedList is threadsafe.

Answer 2

One mistake that strikes me is that LinkedList is not synchronized, but you're trying to write to it in 2 threads.

Another thing to keep in mind is Process.getInputStream() returns the stdout stream of the process, so you should rename the variable currently called stdin to stdout to prevent confusion.

Answer 3

There are known bugs in pre-Vista Windows operating systems where loading DLLs can cause a hang in IO.

e.g. see http://weblogs.java.net/blog/kohsuke/archive/2009/09/28/reading-stdin-may-cause-your-jvm-hang and https://connect.microsoft.com/VisualStudio/feedback/details/94701/loadlibrary-deadlocks-with-a-pipe-read

I'm not sure if this is what you are running in to, but it may be related.

Also, I vaguely recall some issues in getting a valid stdin and stdout from non-console windows applications. If your call to 'test.jar' is using 'javaw' rather than 'java', then this could be the cause of your problem, too.