1. in Interface all the methods are public abstract.this is not necessary with abstract class means abstract class can have concrete methods.
2. all the varible of interface are public static final.this is not necessary with abstract class.
3.abstract class must be inherited.interface must be extended.


in CGI for each request one instance is created which consume resouces.
in Servlet only and only one instance is created by container for servicing many requests.


thanks