Multithreaded Programming in Java: Practical Tips

With the continuous development of computer hardware, the popularity of multi-core CPUs, and the efficiency requirements of modern applications, multi-threaded programming has become an inevitable topic in the field of Java programming. In Java, multi-threaded programming relies on the Thread class and Runnable interface. Java provides a series of thread components that can help us create and manage multiple threads. This article will introduce some practical tips for multi-threaded programming in Java to enable you to better perform multi-threaded programming.

1. Creation and startup of threads

The Thread class in Java is used to create and manage threads. A thread object represents a separate thread. We can create threads by inheriting the Thread class or implementing the Runnable interface. The following is an example of inheriting the Thread class:

public class MyThread extends Thread {
   public void run() {
      // 线程执行的代码
   }
}

We can start a thread through the following code:

MyThread myThread = new MyThread();
myThread.start();

The start() method in the above code will cause the thread to start running and call run ()method.

2. Priority of threads

Every thread in Java has a priority. By default, a thread inherits the priority of the parent process that created it. You can use the setPriority() and getPriority() methods to set and get the priority of the thread:

Thread.currentThread().setPriority(Thread.MAX_PRIORITY);

The above code sets the priority of the current thread to the highest. It should be noted that priority setting is platform-dependent, so overreliance on priority scheduling should be avoided.

3. Thread synchronization

In multi-threaded programming, synchronization between threads is very important. Java provides several mechanisms to achieve thread synchronization, such as the synchronized keyword, ReentrantLock class, etc. The synchronized keyword uses the lock mechanism to ensure synchronization between multiple threads. It can be used to modify methods and code blocks:

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

This method uses the synchronized keyword to ensure thread safety when accessing the count variable.

The ReentrantLock class provides the same locking mechanism as synchronized, but it is more flexible and controllable.

4. Waiting and waking up of threads

Java provides some mechanisms to realize waiting and waking up between threads, such as wait(), notify(), notifyAll( )method. These methods can only be called within a synchronized block, and they are used to control the execution and waiting of the thread:

synchronized(lock) {
   while(!condition) {
      lock.wait();
   }
   // 执行线程需要的操作
   lock.notifyAll();
}

The wait() method in the above code will cause the thread to wait until the condition becomes true. The notifyAll() method will wake up all threads waiting for the object lock.

5. Exception handling of threads

During the execution of a thread, various unexpected situations may occur, such as null pointer exceptions, array out-of-bounds exceptions, etc. In order to avoid these exceptions causing the thread to exit, we can use the try-catch statement to catch the exception:

public void run() {
   try {
      // 线程执行的代码
   } catch(Exception e) {
      // 处理异常
   }
}

Avoiding abnormal thread exit is very important to ensure the stability and reliability of the application.

Summary

This article introduces the practical skills of multi-threaded programming in Java, covering thread creation and startup, priority, synchronization, waiting and waking up, and exception handling. These tips can help us better write multi-threaded applications and improve application efficiency and performance. When doing multi-threaded programming, we should fully consider issues such as thread safety, optimization, and flexibility to ensure the stability and reliability of the application.

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