#Java file synchronization code#

Synchronized method is used to lock an object for any shared resource.If you declare any method as synchronized, it is known as synchronized method.Hence the result is unsynchronized 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). In this example, there is no synchronization, so output is inconsistent. Understanding the problem without Synchronization: By convention, a thread that needs consistent access to an object’s fields has to acquire the object’s lock before accessing them, and then release the lock when it’s done with them.įrom Java 5 the package contains several lock implementations.

Synchronization is built around an internal entity known as the lock or monitor.Every object has an lock associated with it. Mutual Exclusive helps keep threads from interfering with one another while sharing data.

Cooperation (Inter-thread communication).

There are two types of thread synchronization mutual exclusive and inter-thread communication. Here, we will discuss only thread synchronization. before entering into synchronized method or block thread needs to acquire the lock at this point it reads data from main memory than cache and when it release the lock it flushes write operation into main memory which eliminates memory inconsistency errors.

#Java file synchronization code#

JVM guarantees that Java synchronized code will only be executed by one thread at a time.ġ) synchronized keyword in java provides locking which ensures mutual exclusive access of shared resource and prevent data race.Ģ) synchronized keyword also prevent reordering of code statement by compiler which can cause subtle concurrent issue if we don’t use synchronized or volatile keyword.ģ) synchronized keyword involve locking and unlocking. Same is true with what threads are doing with object if all the threads are only reading value then you don’t require synchronization in java. if your shared object is read only or immutable object you don’t need synchronization despite running multiple threads. Synchronization in Java will only be needed if shared object is mutable. If your code is executing in multi-threaded environment you need synchronization for objects which are shared among multiple threads to avoid any corruption of state or any kind of unexpected behavior.