Synchronized method Overriding

Synchronized method Overriding 

Parent Class:

public class Parent{
      public synchronized void function() {
           System.out.println(“function in Parent”);
     }
}

Child Class

public class Child extends Parent {
     public void function() {
          System.out.println(“function in Child”);
     }

}

yes, synchronized method can be overriden. But It’s not thread safe in below scenario.

    Parent a = new Child();

    a.function();
Here overridden synchronized method’s contract can be violated as subclass provides an implementation that is unsafe for concurrent use. 
Vice-Versa : If overriding method i.e method implemented in B class is made synchronized and method in class A is not synchronized , still it is valid overriding.
Best case to ensure thread safety :make both methods , i.e methods declared in super class and child class synchronized.

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