you could see at this table :
Product Product Version Servlet spec JSP spec
Tomcat 3.1 2.2 1.1
Tomcat 3.0 2.2 1.1
Sun J2EE Reference Implementation beta 2.2 ?
Sun JSWDK 1.0.1 2.1 1.0.1
Sun JSDK 2.1 2.1 none
Sun JSDK 2.0 2.0 none
Allaire JRun 3.0 2.2 1.1
Sun Java Web Server 2.0 2.1 -
Sun Java Web Server 1.1 2.0 -
Sun/Netscape iPlanet Web Server 4.1 2.2 ?
and then findout what version  you use.