编写java并发代码案例

很高兴回答你的问题。以下是一个简单的Java并发代码案例：

public class MyThread implements Runnable {
    private int count = 0;

    public void run() {
        for (int i = 0; i < 5; i++) {
            increment();
        }
    }

    public synchronized void increment() {
        count++;
        System.out.println(Thread.currentThread().getName() + "，count = " + count);
    }

    public static void main(String[] args) {
        MyThread myThread = new MyThread();
        Thread thread1 = new Thread(myThread, "Thread 1");
        Thread thread2 = new Thread(myThread, "Thread 2");
        thread1.start();
        thread2.start();
    }
}

这段代码创建了一个实现了Runnable接口的MyThread类。MyThread类有一个共享变量count和一个使用synchronized关键字实现了线程安全的increment方法。在main方法中，它创建了两个线程来执行MyThread的run方法。这两个线程并发执行increment方法，保证了count变量的线程安全性。输出结果如下：

Thread 1，count = 1
Thread 1，count = 2
Thread 1，count = 3
Thread 1，count = 4
Thread 1，count = 5
Thread 2，count = 6
Thread 2，count = 7
Thread 2，count = 8
Thread 2，count = 9
Thread 2，count = 10

希望这个例子可以对你有所帮助！