hi, interface does not have method implementation. only class which implements interface must implememt all the methods defined in interface. My question is why should we implement interface as we can write our own code. In java, Serializable and Cloneable dont have anything inside. How it is useful in serializing and cloning objects. does compiler have anything to understand these interfaces. I have many question regarding interfaces. Can anyone answer to all the possible questions reg-interfaces. Thankyou.