Why HttpServlet also implements Serializable?

[Kousik Majumder]

Hi all,

As we know that if any of the super class implements an interface then the descending classes need not use to implement the interface.

So why HttpServlet implements Serializable interface where as it extends GenericServlet and GenericServlet implements Serializable ?

  
public abstract class HttpServlet
extends GenericServlet
implements Serializable  

 public abstract class GenericServlet
extends Object
implements Servlet, ServletConfig, Serializable   

Thanks,

Kousik
SCJP 5

[Rob Spoor]

Probably just clarity. It makes no difference to remove it, but this way they're saying "please note that this class really is serializable".

[Ben Souther]

By making the servlet serializable, the builders of the servlet API insure that the implementers have the option of serializing the servlet for persistence or load balancing.