Concurrent Programming

Concurrent Programming in Java allows multiple threads to run simultaneously, making programs more efficient and responsive, especially for tasks that are independent or I/O-bound.

Why Concurrency?

  • Efficient CPU utilization
  • Better performance in multi-core systems
  • Responsiveness in interactive applications

Threads in Java

Java supports multithreading through the Thread class and Runnable interface. A thread represents a single sequence of execution within a program.

Creating Threads

1. By Extending Thread Class

class MyThread extends Thread {
    public void run() {
        System.out.println("Thread running...");
    }
}

public class Main {
    public static void main(String[] args) {
        MyThread t1 = new MyThread();
        t1.start();  // Starts a new thread
    }
}

2. By Implementing Runnable Interface

class MyRunnable implements Runnable {
    public void run() {
        System.out.println("Runnable thread running...");
    }
}

public class Main {
    public static void main(String[] args) {
        Thread t = new Thread(new MyRunnable());
        t.start();
    }
}

Thread Lifecycle

  1. New
  2. Runnable
  3. Running
  4. Blocked/Waiting
  5. Terminated

Synchronization

Used to control thread access to shared resources to prevent data inconsistency.

synchronized void printTable(int n) {
    for (int i = 1; i <= 5; i++) {
        System.out.println(n * i);
    }
}

🔗 Related Notes