Java ProcessBuilder waitfor () never competing [duplicate]

Question

This question already has answers here:

process.waitFor() never returns (13 answers)

Closed 7 years ago.

Below is my code.Trying to execute python script but waitfor() never completing . Below is my code. Any suggestions.

String[] command ={"CMD","C:\\Users\\vkode200\\IdeaProjects\\Pythonex1\\TestHello.py"}; 
 ProcessBuilder probuilder = new ProcessBuilder(command );
 //You can set up your work directory
 /*probuilder.directory(new File("c:\\xyzwsdemo"));*/
 Process process = probuilder.start();
 //Read out dir output
 InputStream is = process.getInputStream();
 InputStreamReader isr = new InputStreamReader(is);
 BufferedReader br = new BufferedReader(isr);
 String line;
 System.out.printf("Output of running %s is:\n",
 Arrays.toString(command));
 /*while ((line = br.readLine()) != null) {
 System.out.println(line);
 }
*/
 //Wait to get exit value
 try {
 exitValue = process.waitFor();
 /*exitValue= process.exitValue();*/
 System.out.println("\n\nExit Value is " + exitValue);
 } catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }

• Scary Wombat: Wait to get exit value - maybe still alive? check ps
• ZeusNet: I think you should use python to execute your script and not CMD. have a look here
• user3853393: Thanks ZeusNet i followed what you said and worked for me.

Answer 1

You need to close the process's input stream, and consume all its output on both stdout and stderr, before calling waitFor().

Otherwise it can be blocked trying to read input you aren't sending, or produce output you aren't reading.

• user3853393: Thanks EJP i have closed input stream and also followed ZeusNet suggestion to include python Python instead of cmd and its worked for me.