abstract class means--it has atmost one abstract
method.remaining  might be abstract or not.

interface means ---it has almostall abstract methods.u have
only the method specification.

In real time if u want to share the some common features in
the abstract class  u have to extends the abstract class.
so, u need not wrote the body to the all the methods.
if u implement  interface u should  write body to the all
the methods.

In real time when u extend Abstract class no need t provide 
implementation f all methods & it contains one abstract 
method remaining al r concrete methods
whereas interface we have t provide implementation f all 
methods & by default al r abstract methods

Depending upon the requirement.

Abstract class---->it contains zero or more abstract methods.

ex HttpServlet and GenericServlet
HttpServlet contains all sre concrete methods but it
declared as a Abstract class.

InterFace--->It contains all abstract methods.

if we extends the abstract class .there is chance to extend
another class.

if we implements the interface we can extends another class