Common errors and solutions in Java multi-threaded development

In multi-threaded development, common errors and solutions include: Resource competition errors: Use synchronization mechanisms (locks or synchronized blocks) to prevent multiple threads from accessing shared resources at the same time. Deadlock errors: Use deadlock detection and prevention algorithms (timeout mechanism or hierarchical locking) to avoid waiting for mutual locks. Data inconsistency errors: Use atomic variables or immutable objects to ensure data consistency. Race condition error: Use synchronization mechanisms or encapsulated objects to ensure atomicity of variable operations. Thread safety errors: Clearly mark whether a class or method is thread safe, and use synchronization mechanisms to ensure thread safety.

Common mistakes and solutions in Java multi-threaded development

Multi-threading is an important technology to improve application performance, but Errors are prone to occur during use. Common errors and solutions are as follows:

1. Resource competition

Error:Multiple threads access the share at the same time Resources (such as variables and objects) are not synchronized.

Solution: Use a synchronization mechanism, such as a lock or a synchronized block (synchronized), to ensure that only one thread can access the resource at a time.

// 使用锁
Object lock = new Object();
synchronized (lock) {
    // 操作共享资源
}

2. Deadlock

Error:Multiple threads are waiting for each other to release the lock, causing the system to paralyze.

Solution: Use deadlock detection and prevention algorithms, such as timeout mechanism or hierarchical locking.

// 使用超时机制
Lock lock = ...;
try {
    lock.lock(1000); // 1000ms 超时时间
    // 操作共享资源
} finally {
    lock.unlock();
}

3. Data inconsistency

Error: Inconsistency occurs when data is shared between multiple threads due to thread switching.

Solution: Use atomic variables or immutable objects to ensure data consistency.

// 使用原子变量
AtomicInteger counter = new AtomicInteger();
// 不可变对象
final ImmutableList<String> immutableList = ImmutableList.of("a", "b", "c");

4. Race condition

Error:Multiple threads modify the same variable at the same time, resulting in uncertain results.

Solution: Use synchronization mechanism or encapsulated object to ensure that variable operations are atomic.

// 使用 synchronized 方法
public synchronized int incrementCounter() {
    counter++;
    return counter;
}

5. Thread safety

Error: The class or method does not consider multi-threading scenarios, resulting in thread insecurity.

Solution: Clearly mark whether a class or method is thread-safe, and use appropriate synchronization mechanisms to ensure thread safety.

// 声明类为线程安全
@ThreadSafe
public class MyThreadSafeClass {
    // ...
}

Practical case: Thread pool management

Create a thread pool to manage concurrent tasks and avoid thread creation and destruction overhead:

ExecutorService executor = Executors.newFixedThreadPool(4);
executor.submit(() -> {
    // 任务逻辑
});

Solution With these common mistakes, you can write safe, reliable multi-threaded Java applications.

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