1/30/2024 0 Comments File synchronization javaSo we must use synchronization keyword in java when it is necessary else, we should use Java synchronized block that is used for synchronizing critical section only.This is the second article in the series of articles on Concurrency in Java. A synchronized method in Java is very slow and can degrade performance. In Java, synchronized keyword causes a performance cost. Which is more preferred - Synchronized method or Synchronized block? But other threads can access the rest of the code of the method. This means that no other thread can acquire a lock on the locked object until the synchronized block exits. Synchronized block acquires a lock in the object only between parentheses after the synchronized keyword. It means that no other thread can use any synchronized method until the current thread, which has invoked it's synchronized method, has finished its execution. When we use synchronized keyword with a method, it acquires a lock in the object for the whole method. Difference between synchronized keyword and synchronized block In this example, we are using synchronized block that will make the display method available for single thread at a time.īecause of synchronized block this program gives the expected output. It is capable to make any part of the object and method synchronized. If want to synchronize access to an object of a class or only a part of a method to be synchronized then we can use synchronized block for it. Synchronized public void display(String msg) synchronized void display (String msg) Example : implementation of synchronized method class First This is done by using keyword synchronized with display() method. To synchronize above program, we must synchronize access to the shared display() method, making it available to only one thread at a time. Hence the result is nonsynchronized and such situation is called Race condition. In the above program, object fnew of class First is shared by all the three running threads(ss, ss1 and ss2) to call the shared method(void display). Second ss2 = new Second(fnew, "programmer") In this example, we are not using synchronization and creating multiple threads that are accessing display method and produce the random output. But lets first see what happens when we do not use synchronization in our program. Using Synchronized methods is a way to accomplish synchronization. With synchronization in above case, once T1 starts using temporary.txt file, this file will be locked(LOCK mode), and no other thread will be able to access or modify it until T1 returns. To prevent such problems, synchronization was introduced. Now obviously T1 will return wrong result. Meanwhile, T2 starts and before T1 returns, T2 change the values saved by T1 in the file temporary.txt (temporary.txt is the shared resource). If we do not use syncronization, and let two or more threads access a shared resource at the same time, it will lead to distorted results.Ĭonsider an example, Suppose we have two different threads T1 and T2, T1 starts execution and save certain values in a file temporary.txt which will be used to calculate some result when T1 returns. To enter critical section a thread need to obtain the corresponding object's lock. The synchronization keyword in java creates a block of code referred to as critical section.Įvery Java object with a critical section of code gets a lock associated with the object. The process by which this is achieved is called synchronization. At times when more than one thread try to access a shared resource, we need to ensure that resource will be used by only one thread at a time. The main purpose of synchronization is to avoid thread interference. Synchronization is a process of handling resource accessibility by multiple thread requests. Connecting to Access using Type-1 Driver.Method Overriding with Exception Handling.Difference between Classes And Interface.
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