Solved

•Servlet Callback method ??

Posted on 2004-08-15
3
916 Views
Last Modified: 2013-12-10
•why we say that the followings are Servlet Callback method ?
–doGet
–doPost
–Init
–Destroy

why we use the word "callback".

thanks
0
Comment
Question by:she1
3 Comments
 
LVL 23

Expert Comment

by:rama_krishna580
ID: 11807028
Hi,

A callback method is a method intended to be passed as a parameter. The callee can then call the passed method asynchronously and with whatever parameters it deems appropriate. Callbacks are often used in event handling code.

R.K
0
 
LVL 7

Expert Comment

by:damonf
ID: 11825012
as RK says, a callback method is designed to be called asynchronously.  That is, if object A owns method callback(), and object A enlists object B to perform some work, object B may later call a.callback() with the result of the work.  Object A does not need to maintain a reference to B for this to happen.

doGet and doPost are callbacks because any HTTP client can call them any time.  Init() and destroy() are callbacks because the container can call them anytime if it wishes to start and stop the servlet.  Actually doGet and doPost are really called by the container as well (in reaction to the client's HTTP request).  But they still can be called any time.
0
 
LVL 1

Accepted Solution

by:
fschutte earned 30 total points
ID: 11907693
they are simply callback methods because they are invoked by the container (every container managed component has callback methods because that's the way to communicate with the container)
0

Featured Post

Easy, flexible multimedia distribution & control

Coming soon!  Ideal for large-scale A/V applications, ATEN's VM3200 Modular Matrix Switch is an all-in-one solution that simplifies video wall integration. Easily customize display layouts to see what you want, how you want it in 4k.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Is vFabric an PaaS 1 141
Refresh JTable Content 6 211
how to add # symbol between day week month in java 21 147
Can't start JIRA for the first time 4 100
Configure Web Service (server application) I. Configure security for Web Services methods First, we need to protect Session bean which implements the service: 1. Open EJB deployment descriptor (ejb-jar.xml) in the EJB project that contains you…
Most of the developers using Tomcat find it easy to configure the datasource in Server.xml and use the JNDI name in the code to get the connection.  So the default connection pool using DBCP (or any other framework) is made available and the life go…
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…

860 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question