Creating a method for invoking Karaf shell from inside a pax-exam karaf unit test

gistfile1.java

    @Inject 
    CommandProcessor commandProcessor;
 
    protected String executeCommands(final String ...commands) {
        String response;
        final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        final PrintStream printStream = new PrintStream(byteArrayOutputStream);
        final CommandSession commandSession = commandProcessor.createSession(System.in, printStream, System.err);
        FutureTask<string> commandFuture = new FutureTask<string>(
                new Callable<string>() {
                    public String call() {
                        try {
                            for(String command:commands) {
                             System.err.println(command);
                             commandSession.execute(command);
                            }
                        } catch (Exception e) {
                            e.printStackTrace(System.err);
                        }
                        return byteArrayOutputStream.toString();
                    }
                });

        try {
            executor.submit(commandFuture);
            response =  commandFuture.get(COMMAND_TIMEOUT, TimeUnit.MILLISECONDS);
        } catch (Exception e) {
            e.printStackTrace(System.err);
            response = "SHELL COMMAND TIMED OUT: ";
        }

        return response;
    }