Process exitValue() in Java

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

Syntax:

int java.lang.Process.exitValue()

This method returns the exit value for the process.

Parameters: NA

Returns: the exit value of the process represented by this Process object. By convention, the value 0 indicates normal termination.

Throws:

1. IllegalThreadStateException - if the process represented by this Process object has not yet terminated

Approach 1: When no exception

Java

package com.Process;

import java.io.IOException;

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

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

        // killing the process
        process.destroy();
        System.out.println(process.exitValue());

    }
}

Output:

1

Approach 2: IllegalThreadStateException 

Java

package com.Process;

import java.io.IOException;

public class ProcessexitValue {
    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.exitValue());

    }
}

Output:

Exception in thread "main" java.lang.IllegalThreadStateException: process has not exited
	at java.base/java.lang.ProcessImpl.exitValue(ProcessImpl.java:544)
	at com.Process.ProcessexitValue.main(ProcessexitValue.java:12)

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.