Synchronized Blocks:

 Introduction :

Synchronized blocks in Java provide a way to achieve finer-grained synchronization compared to synchronized methods. 

Instead of synchronizing an entire method, you can use synchronized blocks to lock on specific objects (monitors) to control access to critical sections of code.

This allows for better performance and flexibility when handling multithreaded scenarios where not the entire method needs to be synchronized.


Syntax of Synchronized Blocks:

A synchronized block is defined using the synchronized keyword followed by the object on which the block will be synchronized.

The general syntax is as follows:


synchronized (object) { 
// Critical section of code 
// Only one thread can access this section at a time 
// Modifications to shared data should be done inside this block 
}

The object used in the synchronized block is the monitor that threads will use to acquire the lock.

 Multiple threads can access different synchronized blocks simultaneously, as long as they are synchronized on different objects.


Example of Synchronized Blocks:

Let's use a simple example to illustrate the use of synchronized blocks.

We'll create a Counter class that contains a shared count and two methods, increment() and decrement(), that modify the count in a thread-safe manner using synchronized blocks.


class Counter { 
private int count = 0;
private final Object lock = new Object();
// Synchronization object (monitor)


    public void increment() {
synchronized (lock) { 
 count++;
 }
    } 
public void decrement() {
synchronized (lock) { 
 count--;
        }
 } 
public int getCount() {
synchronized (lock) { 
return count;
        } 
 }
}

In this example, we use an Object called lock as the synchronization object (monitor).

 The increment(), decrement(), and getCount() methods are each surrounded by a synchronized block that synchronizes on the lock object.

 This ensures that only one thread can execute any of these methods at a time.


Using synchronized blocks allows for more granular control over synchronization compared to synchronized methods. In scenarios where different methods need different synchronization, synchronized blocks provide a more efficient solution.


Benefits of Synchronized Blocks:

Granular Control: Synchronized blocks allow you to control the synchronization on specific sections of code, reducing the scope of locking and improving performance in certain cases.

Flexibility: You can synchronize on different objects in different parts of the code, providing flexibility in handling complex synchronization requirements.

Performance: Fine-grained synchronization with synchronized blocks can lead to reduced contention and improved performance in high-concurrency scenarios.


Considerations

Proper Object Selection: Choose the right object to synchronize on to avoid potential deadlocks and ensure proper synchronization of shared data.

Deadlock Avoidance: Avoid nested synchronized blocks that lock on multiple objects simultaneously to prevent potential deadlocks where threads are waiting indefinitely for each other.

Conclusion:

Synchronized blocks in Java offer a flexible and efficient way to achieve thread safety in multithreaded applications. 

By using synchronized blocks, you can control access to critical sections of code while providing better performance compared to synchronizing entire methods.

Careful consideration of object selection and synchronization scope will ensure smooth and reliable concurrent operations in your Java applications.


Remember to balance the need for synchronization with performance considerations. 

Utilize synchronized blocks judiciously to maximize the benefits of concurrency without introducing unnecessary overhead.