Process.waitFor() a thread

Question

While running an external script, I want to read the ErrorStream and OutputStream of this script both simultaneously and separately and then process them further. Therefore, I start a Thread for one of the streams. Unfortunately, the Process doesn't seem to waitFor the Thread to be terminated, but return after the non-threaded stream has no further input.

In a nutshell, here is what I am doing:

ProcessBuilder pb = new ProcessBuilder(script);  
final Process p = pb.start();  

new Thread(new Runnable() {  
  public void run() {
    BufferedReader br = new BufferedReader(new InputStreamReader(p.getErrorStream()));
    ...read lines and process them...
  }
}).start();

BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
...read lines and process them...

int exitValue = p.waitFor();
p.getOutputStream().close();
return exitValue;

Is there any possibility to waitFor the Thread to be terminated?

Answer 1

You can use Thread.join(...) to wait for a Thread to finish. Note that the call throws InterruptedException if the current thread receives an interrupt before the thread you are waiting for finishes.