Java Process waitFor() Method

The waitFor() method of Process class is used to wait the currently executing thread until the process executed by the Process object has been completed. The method returns immediately when the subprocess has been terminated and if the subprocess is not terminated, the thread will be blocked.

Syntax

Parameter

Return

This method generally returns the exit value of the process and subprocesses. By default, normal termination is represented by 0.

Example 1

public class Process_waitForMethodExample1 {
    public static void main(String[] args) {
        try {
            // creating a new process.
            System.out.println("Ms Paint will run.");
            Process p = Runtime.getRuntime().exec("mspaint.exe");
            // waits for the process until you terminate.
            p.waitFor();
            // when you manually close Ms Paint.exe program will continue here
            System.out.println("You have exited from Ms paint.");
        } catch (Exception ex) {
            System.out.println("exception is:"+ex);
        }
    }
}

Output:

Ms Paint will run.
You have exited from Ms paint.

Example 2

public class Process_waitForMethodExample2 {
    public static void main(String[] args) {
        try {
            // creating a new process.
            System.out.println("Ms Paint will run.");
            Process p1 = Runtime.getRuntime().exec("mspaint.exe");
            // waits for the process until you terminate.
            p1.waitFor();
            // when you manually close notepad.exe program will continue here
            System.out.println("You have exit from Ms-paint.");
            System.out.println("Notepad will run.");
            Process p2 = Runtime.getRuntime().exec("notepad.exe");
            // waits for the process until you terminate.
            p2.waitFor();
            // when you manually close notepad.exe program will continue here
            System.out.println("You have exited from Notepad.");

        } catch (Exception ex) {
            System.out.println("Oops! an error has occurred.");             }
    }
}

Output:

Ms Paint will run.
You have exited from Ms-paint.
Notepad will run.
You have exited from Notepad.

Example 3

public class Process_waitForMethodExample3 {
    public static void main(String[] args) {

try{
    System.out.println("Both Ms paint and Notepad will run simultaneously.\n");
        System.out.println("1. Ms Paint will run.");
        Process p1 = Runtime.getRuntime().exec("mspaint.exe");
    System.out.println("2. Notepad will run.\n\n");
    Process p2 = Runtime.getRuntime().exec("notepad.exe");
        // waits for the process until you terminate.
        p1.waitFor();
        // when you manually close notepad.exe program will continue here
        System.out.println("You have exit from Ms-paint.");
    System.out.println("You have exited from Notepad.");
        p2.waitFor();
    } catch (Exception ex) {
        System.out.println("Oops! an error has occurred."); 
    }
   }
 }

Output:

Both Ms paint and Notepad will run simultaneously.

1. Ms Paint will run.
2. Notepad will run.

You have exited from Ms-paint.
You have exited from Notepad.

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