PipedInputStream - How to avoid "java.io.IOException: Pipe broken"

Are you closing your PipedOutputStream when the thread that's using it ends? You need to do this so the bytes in it will get flushed to the corresponding PipedInputStream.

Use a java.util.concurrent.CountDownLatch, and do not end the first thread before the second one has signaled that is has finished reading from the pipe.

Update: quick and dirty code to illustrate my comment below

    final PipedInputStream pin = getInputStream();
    final PipedOutputStream pout = getOutputStream();

    final CountDownLatch latch = new CountDownLatch(1);

    InputStream in = new InputStream() {

        @Override
        public int read() throws IOException {
            return pin.read();
        }

        @Override
        public void close() throws IOException {
            super.close();
            latch.countDown();
        }
    };


    OutputStream out = new OutputStream(){

        @Override
        public void write(int b) throws IOException {
            pout.write(b);
        }

        @Override
        public void close() throws IOException {
            while(latch.getCount()!=0) {
                try {
                    latch.await();
                } catch (InterruptedException e) {
                    //too bad
                }
            }
            super.close();
        }
    };

    //give the streams to your threads, they don't know a latch ever existed
    threadOne.feed(in);
    threadTwo.feed(out);