The moose likes Servlets and the fly likes Debugging servlets Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of Java Interview Guide this week in the Jobs Discussion forum!
JavaRanch » Java Forums » Java » Servlets
Bookmark "Debugging servlets" Watch "Debugging servlets" New topic

Debugging servlets

Danny Duong

Joined: Dec 12, 2002
Posts: 14
Does anyone know how to debug a servlet using Eclipse & Tomcat?
I've created a servlet.
Started Tomcat via Eclipse.
Ran my servlet via a Browser.
But, I don't know how or can't debug the servlet.
Can anyone help?
Or maybe there is a better way to debug servlets
Thanks in advance.
Bhushan Jawle
Ranch Hand

Joined: Nov 22, 2001
Posts: 249
I use Log4j and write log at interested points, view the log file as it gets updated in real time.
Need to find a better way if there is any.
William Brogden
Author and all-around good cowpoke

Joined: Mar 22, 2000
Posts: 13037
The debugging chapter from my Servlets and JSP book is available at:my page for the book.
There is also a downloadable utility that you can use to spy on the exact text of request and response.
Frank Carver

Joined: Jan 07, 1999
Posts: 6920
The best way to debug servlets that I have found is to make it so there is as little code as possible in the servlet itself, and as little code as possible which depends on "non-mockable" Servlet API classes.
I typically have just enough code in the servlet to extract the parameters from the Request and the Writer from the Response, and pass them in to a more testable class for the "heavy lifting".
Once you have this, you can put a simple "main" wrapper round your code (or, even better, a JUnit wapper), and debug and test it under full control on your own desktop, using your favourite tools with no deployment necessary.
Have you tried this ?

Read about me at ~ Raspberry Alpha Omega ~ Frank's Punchbarrel Blog
Michael Bronshteyn
Ranch Hand

Joined: Mar 26, 2002
Posts: 85
you can debug it remotelly.
you can setup to start as debug server and use debugger to connect. if you use bugseeker ( ) it is very easy to setup a project for remote debugging.
you can even debug jsp pages generated servlets, with a little extra work.

Kyle Brown
Ranch Hand

Joined: Aug 10, 2001
Posts: 3892
Ummm... what Tomcat plugin are you using? It SHOULD be as easy as setting a breakpoint in your Servlet and starting Tomcat in Debug mode...

Kyle Brown, Author of Persistence in the Enterprise and Enterprise Java Programming with IBM Websphere, 2nd Edition
See my homepage at for other WebSphere information.
Danny Duong

Joined: Dec 12, 2002
Posts: 14
I'm actually using eclipse as the IDE.
I'm not too sure how to turn on Tomcat for debug.
It is probaly a simple setting - but I don't know how?
If you know how, can you let me know.
I agree. Here's the link:
subject: Debugging servlets
It's not a secret anymore!