A brief analysis of Java's underlying technology: how to implement concurrent programming

As a language widely used in the field of software development, Java has powerful concurrent programming capabilities. The core of implementing concurrent programming is to implement multi-threaded operations through Java's underlying technology. This article will briefly analyze how Java's underlying technology implements concurrent programming and provide specific code examples.

In Java, there are many ways to implement concurrent programming, the most common and basic of which is to use threads (Thread) and locks (Lock). Through threads, we can perform multiple tasks at the same time, thereby improving the execution efficiency of the program. Locks are used to ensure mutually exclusive operations between multiple threads and avoid resource conflicts.

First, let’s take a look at how to use threads to implement concurrent programming. In Java, we can create threads by inheriting the Thread class or implementing the Runnable interface. Specific code examples are as follows:

// 继承Thread类
public class MyThread extends Thread {
    @Override
    public void run() {
        // 线程执行的代码
        System.out.println("线程运行中...");
    }
}

// 实现Runnable接口
public class MyRunnable implements Runnable {
    @Override
    public void run() {
        // 线程执行的代码
        System.out.println("线程运行中...");
    }
}

// 使用线程
public class Main {
    public static void main(String[] args) {
        // 继承Thread类
        MyThread thread1 = new MyThread();
        thread1.start();

        // 实现Runnable接口
        MyRunnable runnable = new MyRunnable();
        Thread thread2 = new Thread(runnable);
        thread2.start();
    }
}

In the above code, we create two threads, one is created by inheriting the Thread class, and the other is created by implementing the Runnable interface. In the thread's run() method, we can define the specific code to be executed by the thread. After starting a thread using the start() method, the thread will execute code in its own independent execution space.

Next let’s take a look at how to use locks to implement mutual exclusion operations between multiple threads. In Java, we can use the synchronized keyword or Lock interface to implement the lock function. The specific code examples are as follows:

// 使用synchronized关键字
public class Counter {
    private int count = 0;

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

    public synchronized int getCount() {
        return count;
    }
}

// 使用Lock接口
public class Counter {
    private int count = 0;
    private Lock lock = new ReentrantLock();

    public void increment() {
        lock.lock();
        try {
            count++;
        } finally {
            lock.unlock();
        }
    }

    public int getCount() {
        lock.lock();
        try {
            return count;
        } finally {
            lock.unlock();
        }
    }
}

// 使用锁
public class Main {
    public static void main(String[] args) {
        Counter counter = new Counter();

        for (int i = 0; i < 10; i++) {
            Thread thread = new Thread(() -> {
                for (int j = 0; j < 1000; j++) {
                    counter.increment();
                }
            });
            thread.start();
        }

        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("Count: " + counter.getCount());
    }
}

In the above code, we use two methods to implement the lock function: synchronized keyword and Lock interface. Whether using the synchronized keyword or the Lock interface, they can ensure mutually exclusive operations between multiple threads. In the sample code, we create a Counter class to count and use locks to implement incr

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