Java – Thread Synchronization

Thread Synchronization:

• Synchronization is the concept of allowing thread sequentially when multiple threads trying to access the resource.
• We implement synchronization using ‘synchronized’ keyword.
• We can synchronize either Block or Method.

Program: Consider a method increase the value of x by 1 and when multiple threads are trying to invoke the method concurrently, we get odd results. Hence we need to synchronize the value() method.

class Modify {             static int x;             synchronized static void value()             {                         x=x+1;             } } class First extends Thread {             public void run()             {                         for (int i=1 ; i<=100000 ; i++)                         {                                     Modify.value();                         }             } } class Second extends Thread {             public void run()             {                         for (int i=1 ; i<=100000 ; i++)                         {                                     Modify.value();                         }             } } class Synchronization {             public static void main(String[] args)             {                         First t1 = new First();                         Second t2 = new Second();                         t1.start();                         t2.start();                         try                         {                                     t1.join();                                     t2.join();                         }                         catch(Exception e){}                         System.out.println(“Final x value : ” + Modify.x);             } }