what is synchronization in java

Category : Java | Sub Category : Java Interview questions | By Prasad Bonam Last updated: 2023-07-08 15:16:03 Viewed : 335

what is synchronization in java

In Java, synchronization is a mechanism used to control access to shared resources or critical sections of code in a multithreaded environment. It ensures that only one thread can access the synchronized block or method at a time, preventing concurrent access and potential data inconsistencies or race conditions.

The synchronized keyword is used to achieve synchronization in Java. There are two ways to apply synchronization:

1. Synchronized Blocks: A synchronized block is used to surround a critical section of code that should be executed atomically by only one thread at a time. The syntax for a synchronized block is as follows:

javaCopy code
synchronized (object) {
    // Critical section of code
}

The object is an optional parameter that represents the lock on which the synchronization is based. It can be any Java object, but it should be the same object for all threads that need to synchronize on the same block of code.

2. Synchronized Methods: A synchronized method is a method that is declared with the synchronized keyword. When a thread invokes a synchronized method, it acquires the lock associated with the object on which the method is invoked. Other threads that try to invoke synchronized methods on the same object will be blocked until the lock is released. The syntax for a synchronized method is as follows:

javaCopy code
public synchronized void methodName() {
    // Method implementation
}

The entire method body is considered as a critical section, and only one thread can execute it at a time.

Synchronization ensures that concurrent threads can safely access shared resources without causing data corruption or unexpected behavior. It provides mutual exclusion and establishes a happens-before relationship, ensuring memory visibility and preventing race conditions.

Its important to note that excessive or unnecessary use of synchronization can lead to performance issues in multithreaded applications. Therefore, its recommended to use synchronization only when necessary and consider alternative synchronization mechanisms like locks, concurrent collections, or higher-level synchronization constructs like the java.util.concurrent package when appropriate.