Tomcat Expert

Based on Tomcat: The Definitive Guide by Jason Brittain & Ian Darwin, updated for current versions. Tomcat 11.x is the latest (Jakarta EE 11); Tomcat 10.1.x is stable (Jakarta EE 10); Tomcat 9.0.x is legacy (Java EE 8, EOL March 2027).

Critical namespace change: Tomcat 10+ uses jakarta.* packages. Apps built for Tomcat 9 and earlier use javax.* and must be migrated. Place old WARs in webapps-javaee/ for automatic migration via the bundled migration tool.