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Java Threads

Threads in Java allow concurrent execution of two or more parts of a program to maximize the utilization of CPU. Multithreading is a Java feature that allows concurrent execution of two or more parts of a program for maximum utilization of CPU.

1. Creating Threads

You can create a thread in Java in two ways:

  • By extending the Thread class.
  • By implementing the Runnable interface.

1.1 Extending the Thread Class

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

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

1.2 Implementing the Runnable Interface

public class MyRunnable implements Runnable {
    @Override
    public void run() {
        System.out.println("Thread is running.");
    }
}

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

2. Thread Methods

  • start(): Starts the thread by calling its run() method.
  • sleep(long milliseconds): Causes the thread to sleep for the specified time.
  • join(): Waits for the thread to die.
  • getName() and setName(String name): Gets or sets the thread's name.

3. Thread Synchronization

Synchronization is used to control access to shared resources in multithreaded applications to prevent data inconsistency.

Example: Using the synchronized Keyword

public class Counter {
    private int count = 0;

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

    public int getCount() {
        return count;
    }
}

4. Thread Communication

Threads can communicate using methods like wait(), notify(), and notifyAll().

5. Key Takeaways

  • Threads enable concurrent execution in Java.
  • Create threads by extending Thread or implementing Runnable.
  • Use synchronization to control access to shared resources.
  • Be cautious of issues like deadlocks and race conditions.
  • Proper thread management is crucial for application performance and reliability.
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