If yous et the "targeted runtime" to an application server (like JBoss for example), then Eclipse should pick up the vendor-provided Jar files automatically. Did you set a targeted runtime for your project?
How to Add servlet jar in your eclipse project class path.?
Please help me out.
I'm a beginner.
You need to let Eclipse know that your application is going to run on your particular application server. For example, if you plan to deploy your application to JBoss Application Server, you tell Eclipse this, and Eclipse will include the proper JBoss jar files on the build path.
You do this by setting a Targeted Runtime. This is set in the Project properties. In Eclipse, go to Project -> Properties, then click on the Targeted Runtimes page. On that page, you can select the runtime (application server) your application will use.
By the way, this is actually an Eclipse (IDE) question, not a Servlet question. If you continue to have problems, you should begin your own Topic in the IDE forum.