Java Synchronization:
📌 What is Synchronization in Java?
Synchronization in Java is a technique used to control the access of multiple threads to shared resources. It ensures that only one thread can access a critical section of code at a time, preventing thread interference and data inconsistency.
📌Why is Synchronization Important?
- Prevents race conditions in multithreading.
- Ensures data consistency in concurrent execution.
- Helps in avoiding deadlocks when managing shared resources.
📌Types of Synchronization in Java:
1. Process Synchronization:
Process synchronization ensures that multiple processes do not execute critical sections simultaneously. Examples include system applications like Microsoft Word and Acrobat Reader running as independent processes.
2. Thread Synchronization:
Thread synchronization ensures that multiple threads do not access a shared resource concurrently. It can be categorized into:
- Mutual Exclusion: Prevents simultaneous execution of critical sections.
- Inter-Thread Communication: Allows threads to communicate with each other.
📌Lock Mechanism in Java:
Java uses an internal mechanism called a monitor (lock) for synchronization. When a thread enters a synchronized block, it acquires a lock on the object. This lock is released once the thread completes execution, ensuring exclusive access to the shared resource.
📌Implementing Synchronization in Java:
1. Using the Synchronized Method-
A method declared with the synchronized keyword ensures that only one thread can execute it at a time.
Example Code:
class MathService {
synchronized void getSumOfArray(int[] numbers) {
int sum = 0;
for (int number : numbers) {
System.out.println(Thread.currentThread().getName() + " adds " + sum + " to " + number + " to get -> " + (sum += number));
try {
Thread.sleep(500);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
}2. Using Synchronized Block:
If you need to synchronize only a specific portion of code instead of an entire method, you can use a synchronized block.
Example Code:
class MathService {
void getSumOfArray(int[] numbers) {
synchronized (this) {
int sum = 0;
for (int number : numbers) {
System.out.println(Thread.currentThread().getName() + " adds " + sum + " to " + number + " to get -> " + (sum += number));
try {
Thread.sleep(500);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
}
}3. Using Static Synchronization:
Static synchronization ensures that a shared resource is locked at the class level, preventing multiple objects from interfering with each other.
Example Code:
class MathService {
synchronized static void getSumOfArray(int[] numbers) {
int sum = 0;
for (int number : numbers) {
System.out.println(Thread.currentThread().getName() + " adds " + sum + " to " + number + " to get -> " + (sum += number));
try {
Thread.sleep(500);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
}📌Advantages of Java Synchronization:
- Prevents Data Inconsistency: Ensures that shared resources are accessed by only one thread at a time.
- Avoids Race Conditions: Eliminates the risk of multiple threads modifying data simultaneously.
- Ensures Thread Safety: Synchronization helps in maintaining thread-safe operations in Java applications.
📌Disadvantages of Synchronization in Java:
- Performance Overhead: Synchronization increases execution time as only one thread can access a resource at a time.
- Thread Blocking: Threads must wait for their turn, leading to inefficiency in high-performance applications.
📌Summary:
- Synchronization in Java controls thread access to shared resources.
- Synchronized methods and blocks help prevent race conditions.
- Static synchronization ensures thread safety at the class level.
- Pros: Prevents data inconsistency and ensures thread safety.
- Cons: May lead to performance overhead due to thread blocking.
📌Conclusion:
Understanding Java synchronization is crucial for developers working on multithreaded applications. It ensures data integrity, prevents deadlocks, and optimizes parallel execution for high-performance applications. By carefully implementing synchronization techniques, Java developers can build robust and scalable software solutions.
