Capturing output of executed command with piped streams.

exec.java

final PipedInputStream stream = new PipedInputStream();
final Process start = Runtime.getRuntime().exec(this.command);
new Thread(new Runnable() {
    @Override
    public void run() {
        try {
            InputStream inputStream = start.getInputStream();
            PipedOutputStream output = new PipedOutputStream(stream);

            IOUtils.copy(inputStream, output);
            output.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}).start();
start.waitFor();

ANTLRInputStream input = new ANTLRInputStream(new InputStreamReader(stream));