Process onExit() in Java

onExit(): This method is available in the java.lang.Process class of Java.

Syntax:

CompletableFuture<Process> java.lang.Process.onExit()

This method returns a CompletableFuture<Process> for the termination of the Process.

The java.util.concurrent.CompletableFuture provides the ability to trigger dependent functions or actions that may be run synchronously or asynchronously upon process termination.

When the process has terminated the CompletableFuture is completed regardless of the exit status of the process.

Parameters: NA

Returns: a new CompletableFuture<Process> for the Process.

Exceptions: NA

Approach

Java

package com.Process;

import java.io.IOException;

public class ProcessonExit {
    public static void main(String[] args) throws IOException {

        ProcessBuilder builder = 
                       new ProcessBuilder("notepad.exe");
        // creating the process
        Process process = builder.start();

        System.out.println(process.onExit());

        // killing the process
        process.destroy();

    }
}

Output:

java.util.concurrent.CompletableFuture@2471cca7[Not completed]

Some other methods of Process

children(): This method returns a snapshot of the direct children of the process. The parent of a direct child process is the process. Typically, a process that is not alive has no children.

descendants(): This method returns a snapshot of the descendants of the process.

destroy(): This method kills the process.

destroyForcibly(): This method kills the process forcibly. The process represented by this Process object is forcibly terminated.

exitValue(): This method returns the exit value for the process.

getErrorStream(): This method returns the input stream connected to the error output of the process.

getInputStream(): This method returns the input stream connected to the normal output of the process.

getOutputStream(): This method returns the output stream connected to the normal input of the process.

info(): This method returns a snapshot of information about the process.

isAlive(): This method tests whether the process represented by this Process is alive.

onExit(): This method returns a CompletableFuture<Process> for the termination of the Process.

pid(): This method returns the native process ID of the process.

supportsNormalTermination(): This method returns true if the implementation of destroy is to normally terminate the process, Returns false if the implementation of destroy forcibly, and immediately terminates the process.

toHandle(): This method returns a ProcessHandle for the Process.

waitFor(): This method causes the current thread to wait, if necessary until the process represented by this Process object has terminated. This method returns immediately if the process has already been terminated.

waitFor(long, TimeUnit): This method takes two arguments. This method causes the current thread to wait, if necessary until the process represented by this Process object has terminated, or the specified waiting time elapses.