why do tomcat or for that matter any other servlet contaier requires JVM ? there is no main method in the servlets/jsp and the lifecycle of servlets/jsp is managed by container so why the need of JVM ? am i missing something here ? the other day i was installing glassfish in eclipse and it only asked me that it required JDK. so i selected JDK in the option where it askes for VM. shouldnt it be the same case for tomcat as well ?