One of the aspects we have to work around building and improving a dynamic language implementation on the Java Virtual Machine is the way the JVM loads and executes bytecode. In order for JRuby to take advantage of the Hotspot just-in-time (JIT) compiler,
Lets imagine that you have a list view of some data which takes a long time to generate, one second or so to suck the data from the database. This is unreasonable for a site of any proportion, and you certainly don’t want to re-run query every time some