Java Implement Multiple Interfaces With Same Default Method

To understand how to implement multiple interfaces with the same method name we take an example. Default method and multiple inheritance ambiguity problems since java classes can implement multiple interfaces and each interface can define a default method with the same method signature the.

Solved Which Of The Following Is True About Interfaces In

In the example below clickable and accessible both define the print method.

Java implement multiple interfaces with same default method. This is a clear conflict with respect to inheritance. The implementation class should define explicitly specify which default method to use or define it s own one. Interfaces methods must be implemented by the concrete class that implements them.

Of course in your example it s a bad idea to have two interfaces declaring the same method. Multiple defaults. In this example we take two interfaces named as g1 and g2 with the same method name.

Java 8 introduces default method so that list collection interface can have a default implementation of foreach method and the class implementing these interfaces need not implement the same. C allows the implementation of multiple interfaces with the same method name. Now in your case both interface say that concrete class must implement methods eat and travel so when you implement both interfaces you only need a single implementation.

Syntax public interface vehicle default void print system out println i am a vehicle. Now suppose there are two interfaces then both say the same thing that concrete class must implement the method eat. If both of the implemented interfaces define a default method with same method signature then the implementation class does not know which default method to use.

More practically you should have made an interface player with method play and have two other more specific interfaces dvdplayer and cassetteplayer with specific methods for dvds and cassettes who inherit from player. It effectively means that for the compiler there is only one method which is visible in the scope of your class implementing both the interfaces. Default methods and multiple inheritance in case both the implemented interfaces contain default methods with same method signature the implementing class should explicitly specify which default method is to be used or it should override the default method.

No its an error if two interfaces contain a method with the same signature but different return types then it is impossible to implement both the interface simultaneously. According to jls 8 4 2 methods with same signature is not allowed in this case.

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