The default method in an interface is a method with a predetermined body. The word default is used. In Java 8, default methods were added for "Backward Compatibility" in the event that the JDK changed any interfaces. All classes that implement the interface will break if a new abstract method is added, and they will all need to implement the new method. The interface conforming classes won't experience any effects from default methods. In the implementation, default methods can indeed be overridden if necessary. Additionally, it is neither synchronised nor final.