To run J2EE , first thing is you should install Tomcat (or any web
application server) .
You should have the plugin folder for the respective server. Place
the plugin folder in 'plugins' folder or eclipse.

Now, Eclipse has the three icons (i.e., start, stop and restrart )
displayed on its console. You can also see 'Tomcat' in the main
menu.Next thing is to give the path of tomcat to the eclipse.
You may follow the following steps:

In Eclipse console go to 'Windows'--->'Preferences'--->'Tomcat'.
Among the radiobuttons displayed for Tomcat versions select the
relevant radio button for you Tomcat.

Against the 'Tomcat home' give the path of your Tomcat home. For Eg:
D:\apache_Tomcat5

In the context declaration mode, select the 'Context files' option.
click apply and then OK.

Second step: Under Tomcat ...we have 'Advanced' options. In that
Advanced screen give the tomcat base against the Tomcat base.
Click 'Apply' and then 'OK'.

Now, the tomcat has been set.

Next thing is creating a project. This is similar to J2SE except we
have to select Tomcat Project. Or we can also proceed by selecting
Java Project and then creating WEB-INF folder.

After creating the project, right click on this folder which gives
the option to create servlet , jsp etc.