Comment 4 for bug 568823

An additional possibility is to specify the JVM using the "-server" flag. Although Java also will auto-set this based on the machine "class", currently it will only choose the server JVM one machines with 2GB+ of RAM and 2 cores. Interestingly, the 32bit instances offered by EC2 (a popular choice for hosting web frontends) have 1.7GB of RAM, which would cause the client VM to be auto-selected.

http://java.sun.com/docs/hotspot/HotSpotFAQ.html#compiler_types
http://java.sun.com/j2se/1.5.0/docs/guide/vm/server-class.html