What if a class implements two interfaces which have default methods with same name and signature?

Interfaces in Java are used to provide multiple inheritances. Classes can implement more than one interface. As interface can consist of default methods in Java 8, which a class does not necessarily need to implement. We can have two interfaces that have default methods with the same name and signature.

Let's create two interfaces with the same default method:

public interface Interface1 { 
   default void hello(){ 
      System.out.println("Hello from Interface1"); 
   } 
} 
 
public interface Interface2 { 
   default void hello(){ 
      System.out.println("Hello from Interface1"); 
   } 
} 

So, we have two interfaces with the default method hello with the same signature:

public class InterfaceImpl implements Interface1,Interface2{ 
   @Override 
   public void hello() { 
      Interface1.super.hello(); 
   } 
} 

Now, once you create a class that implements both of these interfaces, the compiler will force you to override the hello method. You can call hello of any of the interfaces if you want using the syntax given previously or you can given a different implementation to it.