Feb 08, 2019 In Java, a synchronized block of code can only be executed by one thread at a time. Also, java supports multiple threads to be executed concurrently. This may cause two or more threads to access the same fields or objects at same time. Please note that we can use synchronized keyword in the class synchronized java class object The Class object that represents the runtime class of this object. See The Java Language Specification: Class Literals The class Object does not itself implement the method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked. A
A synchronized block in Java is synchronized on some object. All synchronized blocks synchronized on the same object can only have one thread executing inside them at a time. All other threads attempting to enter the synchronized block are blocked until the thread inside the synchronized block exits the block. synchronized java class object
Thus access to class's static fields is controlled by a lock that's distinct from the lock for any instance of the class. Synchronized Statements. Another way to create synchronized code is with synchronized statements. Unlike synchronized methods, synchronized statements must specify the object that provides the intrinsic lock: The synchronized code has to synchronize using the same object instance across all threads. Classes are objects too! There's typically just one instance of a given Class's object, created when the class Synchronized methods enable a simple strategy for preventing thread interference and memory consistency errors: if an object is visible to more than one thread, all reads or writes to that object's variables are done through synchronized methods. synchronized java class object Java Synchronized Block for. class. Ask Question 92. 43. What does this java code mean? Will it gain lock on all objects of MyClass? Difference between class locking and object locking in Java. 0. Java Synchronization inside Another Thread. 2. puzzled when using synchronized lock. 0. Dec 17, 2016 Can we make class as synchronized in Java? Update Cancel. Answer Wiki. 4 Answers. Anubhav Soin, Keep it simple. Answered Dec 18, 2016. Your query is prone to ambiguous interpretation. What exactly is class synchronization. If you mean synchronization on the object of class, then yes. Just to clear the above statement more precisely. Synchronized static methods are synchronized on the class object of the class the synchronized static method belongs to. Since only one class object exists in the Java VM per class, only one thread can execute inside a static synchronized method in the same class. Is it not suppose to wait till the synchronized object gets unlocked? The lock is held by the thread, so the fact that you're synchronizing on it twice (in the case of the first call to doSomething in main) doesn't matter, it's on the same thread. If another thread then tried to enter a synchronized block on objToSync, that other thread would wait until this thread released all of its locks.