Process process = pb.start();

        Future<String> stdoutFuture = readStreamAsync(process.getInputStream());
        Future<String> stderrFuture = readStreamAsync(process.getErrorStream());

        int returnCode = process.waitFor();
        String stdout = stdoutFuture.get();
        String stderr = stderrFuture.get();
        return new ExecResult(stdout, stderr, returnCode);
    }