Solved: get own pid

Getting your own PID or Process Identification Number is an essential part of Java programming. The PID is a unique number that identifies each process in a system which is used by the operating system’s scheduler to manage all running processes. In our first part, we will look into how to get your own PID using Java.

Although there’s no standard way provided by Java to get process ID. However, there are some workarounds which we’ll leverage to obtain PID.

Java’s ManagementFactory to Get Own PID

Java releases after Java 9 have equipped with a way to get the PID from the `ProcessHandle`:

public class PidExample {
    public static void main(String[] args){
        long PID = ProcessHandle.current().pid();
        System.out.println("PID: " + PID);
    }
}

In the above code, `ProcessHandle.current().pid()` returns the PID of the current process or the Java Virtual Machine. You can then print or use this PID wherever needed.

Getting PID with Legacy Java Version

For those who are using Java 8 or an older version which lack `ProcessHandle`, they can get the PID via `ManagementFactory.getRuntimeMXBean().getName()`:

import java.lang.management.ManagementFactory;

public class PidExampleLegacy {
    public static void main(String[] args){
        String jvmName = ManagementFactory.getRuntimeMXBean().getName();
        long PID = Long.parseLong(jvmName.split("@")[0]);
        System.out.println("PID: " + PID);
    }
}

This older method involves splitting the JVM name from `@` and parsing the PID from the string form.

The code first gets the JVM name as a form like ‘pid@hostname’. By splitting this string at ‘@’, it retrieves the PID. This method can indeed give errors if the JVM does not follow the ‘pid@hostname’ form. However, most JVMs do, making it a historically safe bet.

Wrapping Up

It’s important to understand the role of PIDs in operating systems and how they are managed . This knowledge lends to the power, control, and flexibility one has when developing system-level applications. In Java programming, there’s a direct way to get the PID in recent releases, and there are alternative ways for legacy versions. We should use this information responsibly, knowing that misuse can lead to system instability.