Question: can jdk run on tomcat?
Answer: Minimum version of JRE depends on the version of Tomcat: for Tomcat 6.0 it is Java 5, for Tomcat 7.0 - Java 6. However you can also use JDK because, as you probably know, it includes JRE (link). ... If you use JRE you should set JRE_HOME, if JDK - JAVA_HOME. Read RUNNING.