The part about Tomcat certainly isn't true, unless the author is using a different distribution than what you get from the project's website. The Tomcat startup

The part about Tomcat certainly isn't true, unless the author is using a different distribution than what you get from the project's website. The Tomcat startup scripts do not set any heap size paramters; until recently the default Sun JVM behavior was to set a max heap size of only 64MB. This logic changed a few versions ago to use a fractional amount of the total memory size on the machine, but for dedicated hosts this is still rarely the setup you want. Perhaps the author is using a packaged version of Tomcat from his OS distributor.