java restartApplication Method only restarts once?

Question

I was trying to use a restartApplication method that I found on stack overflow, but for some reason it only will restart my application once. For example, in this simple JOptionPane program below, if the user enters the letter "a", it will restart the program. Once the program restarts, if the user types in "a" again, it just terminates the execution. How can I enable it to restart itself continuously?

I added in some println() statements to see if I could get any more info, and it just confirmed that the program is ending right after I type in the letter "a" on the second time around.

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import javax.swing.JOptionPane;


public class JOptionTest{
public static void restartApplication()
{
  final String javaBin = System.getProperty("java.home") + File.separator + "bin" + File.separator + "java";
  final File currentJar = new File("C:\\Documents and Settings\\My Documents\\hello3.jar");//UpdateReportElements.class.getProtectionDomain().getCodeSource().getLocation().toURI());

  /* is it a jar file? */
  if(!currentJar.getName().endsWith(".jar"))
    return;

  /* Build command: java -jar application.jar */
  final ArrayList<String> command = new ArrayList<String>();
  command.add(javaBin);
  command.add("-jar");
  command.add(currentJar.getPath());

  final ProcessBuilder builder = new ProcessBuilder(command);
  try {
    builder.start();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
  System.exit(0);
}


public static void main(String[] args){
    String str = JOptionPane.showInputDialog(null, "Enter some text",1);
    System.out.println(str);
    //String a= "a";
    if (str.equals("a")){
        System.out.println(str+ "right about to restart");
        restartApplication();
    }
}
}

Why are you creating a new process to run another Java application? This has a bad smell about it. — Andrew Thompson, Aug 11 '12 at 03:37
Perhaps I was misunderstood. There is only one Java application in the mix. — davidVee, Aug 13 '12 at 18:46

score 3 · Accepted Answer · answered Aug 10 '12 at 17:57

See this line?

System.exit(0);

you are calling restartApplication a Single time and when it ends you exit the java process.

If you want to restart continuously, then remove this line and probably iterate forever:

 public static void restartApplication()
 {
  while(true){

       final String javaBin = System.getProperty("java.home") + File.separator + "bin" + File.separator + "java";
       final File currentJar = new File("C:\\Documents and Settings\\XBBKKYL\\My      Documents\\hello3.jar");//UpdateReportElements.class.getProtectionDomain().getCodeSource().get           Location().toURI());

      /* is it a jar file? */
     if(!currentJar.getName().endsWith(".jar"))
       return;

   /* Build command: java -jar application.jar */
    final ArrayList<String> command = new ArrayList<String>();
    command.add(javaBin);
    command.add("-jar");
    command.add(currentJar.getPath());

    final ProcessBuilder builder = new ProcessBuilder(command);
    try {
        builder.start();
    } catch (IOException e) {
       e.printStackTrace();
    }
  }
}

I have not tested this, it's just an idea

This works perfectly on this program. When I comment out that line in my actual program(decided it was too long to post on stack overflow), it restarts as many times as I want, but it never closes the old instances. Do you know how I can get it to close the old instances? I guess it's technically not restarting if it doesn't actually close the old instances. — davidVee, Aug 10 '12 at 18:41
@davidVee the start() method from ProcessBuilder creates a new Process, you can call destroy() on that process. — Eugene, Aug 10 '12 at 18:50

java restartApplication Method only restarts once?

1 Answers1

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