Concurrency in Java

Java provides rich APIs for handling multithreading and concurrent programming. These allow programs to make better use of system resources and handle multiple tasks simultaneously.

⚠️ Concurrency is powerful but hard to get right — race conditions and deadlocks can ruin your day!

Creating Threads

public class MyThread extends Thread {
    public void run() {
        System.out.println("Running in thread: " + Thread.currentThread().getName());
    }
}

Thread t = new MyThread();
t.start();

Using Runnable

Runnable task = () -> System.out.println("Runnable Task");
new Thread(task).start();

Thread Lifecycle

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

Synchronization

public synchronized void increment() {
    count++;
}

Locks and Executors

Lock lock = new ReentrantLock();
lock.lock();
try {
    // critical section
} finally {
    lock.unlock();
}

ExecutorService executor = Executors.newFixedThreadPool(2);
executor.submit(() -> doWork());
executor.shutdown();

Common Pitfalls

• Race Conditions
• Deadlocks
• Starvation

❗ Always consider thread safety when working with shared resources.

Summary

Java offers both high-level and low-level concurrency APIs. Learn to use them effectively to build performant, responsive apps.

🔍 “Concurrency is not parallelism.” – Rob Pike