Synchronized keyword in java javatpoint

Dylan 165 Published: 12/24/2024

Synchronized keyword in java javatpoint

I'm happy to help! Here's an explanation of synchronized keyword in Java:

In Java, the synchronized keyword is used to ensure that a specific method or block of code is executed by only one thread at a time. This is known as mutual exclusion or exclusive access.

When you use the synchronized keyword on a method or block of code, it means that any thread that tries to execute that code must first acquire a lock on the object. If another thread already has the lock, then the second thread will be blocked until the first thread finishes executing and releases the lock.

Here are some key benefits of using synchronized:

Thread safety: By ensuring that only one thread can execute a block of code at a time, you can prevent concurrent modification or access to shared resources. Prevents starvation: If multiple threads are waiting to acquire the same lock, Java ensures that each thread gets a fair chance to execute by implementing a "fair" scheduling algorithm. Supports synchronization primitives: Synchronized methods and blocks of code can be used to implement more advanced concurrency control mechanisms like semaphores, monitors, and barriers.

When to use synchronized:

Accessing shared state: When multiple threads need to access and modify shared data or resources, using synchronized ensures that only one thread can do so at a time. Modifying shared resources: If you have shared resources like files or databases that need to be updated by only one thread at a time, use synchronized to ensure thread safety. Implementing locks: Synchronized methods and blocks of code can be used as a low-level lock implementation for more complex concurrency control mechanisms.

Some important points to keep in mind:

Performance overhead: Using synchronized can introduce some performance overhead due to the additional locking mechanism. Avoid unnecessary synchronization: Be mindful of the scope of your synchronized blocks or methods and avoid unnecessary synchronization, as it can lead to poor performance and bottlenecks.

Best practices for using synchronized:

Use at the finest grain possible: Synchronize only the specific code that requires mutual exclusion. Avoid synchronizing entire objects: Instead, synchronize individual methods or blocks of code within an object. Use volatile when necessary: If you need to share data between threads and ensure visibility of changes, use volatile keywords.

In conclusion, the synchronized keyword in Java is a powerful tool for ensuring thread safety and mutual exclusion in your programs. By using it wisely and following best practices, you can write robust and efficient concurrent code.

Source:

Oracle Java Tutorials: Synchronizing Threads javatpoint: Synchronized Keyword in Java

References:

[1] Java SE 11 API Documentation: Synchronization Keywords

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What is synchronized keyword in Java static method?

I'll respond in English as per your request.

The synchronized keyword in Java is used to create a block of code that can only be accessed by one thread at a time, ensuring that only one thread can execute the code within the synchronized block simultaneously. This keyword is particularly important when dealing with multithreading, as it helps prevent conflicts and ensures data consistency.

In the context of static methods in Java, synchronized is used to synchronize access to static fields or methods. When a static method is marked as synchronized, it means that only one thread can execute this method at any given time, ensuring that no concurrent modifications occur.

When you use the synchronized keyword with a static method, the Java Virtual Machine (JVM) uses an internal lock, known as a "static lock," to enforce synchronization. This means that even if multiple threads are calling the same static method simultaneously, only one thread will execute the code within the synchronized block at any given time.

Here's how you can use synchronized with a static method in Java:

public class Example {
public static synchronized void myMethod() {
// Code that needs to be executed in a thread-safe manner
}
}

In this example, myMethod() is a static method that can only be accessed by one thread at a time. If multiple threads try to call myMethod() simultaneously, they will be forced to wait until the previous thread has finished executing the code within the synchronized block.

The benefits of using synchronized with static methods include:

Thread safety: By ensuring that only one thread can execute the code at any given time, you can prevent concurrent modifications and ensure data consistency. Avoidance of race conditions: When multiple threads are accessing shared resources simultaneously, a race condition can occur where different threads modify the same resource in ways that are inconsistent with each other. synchronized helps avoid such race conditions by ensuring exclusive access to static fields or methods. Improved overall system performance: By preventing concurrent modifications and ensuring thread safety, you can improve the overall performance of your Java application.

In summary, using synchronized with static methods in Java provides a way to ensure thread safety, prevent race conditions, and improve overall system performance by controlling access to shared resources.