if i declare any fields in the classi.e not in any methods...they r given a default value,i.e for int its zero(0)..these are instance fields..........an object is an instance of a classi.e the object created is of the class type.

          well, in an interface you can only define the prototype of the methods,it cant contain any implimentations,while in an abstract class there can be absract methods and also implimentations of the method which are not abstract