Calling the Run Method in Java

In Java, the run() method is the entry point for a thread's execution. When a thread is started, the run() method is executed in a separate call stack. However, it can also be called directly, but this will not create a new thread.

Key Points about the Run Method:

• Thread Execution: The run() method contains the code that defines the thread's behavior and actions during execution.
• Direct Call: Calling run() directly does not start a new thread. It runs in the current thread context, just like any other method.
• Overriding: To customize a thread's behavior, you can override the run() method in a class that implements Runnable or extends the Thread class.
• Thread Lifecycle: Once a thread is started using start(), the run() method executes independently of the main program flow.

Syntax of the Run Method:

The basic syntax of the run() method is as follows:

public void run() {
    // Code to be executed by the thread
}

Example of Calling the Run Method:

This example demonstrates both starting a thread using the start() method and calling the run() method directly.

public class RunExample extends Thread {
    public void run() {
        System.out.println(Thread.currentThread().getName() + " is executing the run method.");
    }

    public static void main(String[] args) {
        RunExample thread1 = new RunExample();

        // Calling the run method directly
        thread1.run(); // This does not start a new thread

        // Starting a new thread
        RunExample thread2 = new RunExample();
        thread2.start(); // This will execute the run method in a new thread
    }
}

Output:

Conclusion:

Understanding the difference between calling the run() method directly and starting a thread using start() is crucial in Java multithreading. Always use start() to execute run() in a new thread to achieve true concurrent execution.