H2, more than anything else, is great for testing. It can emulate oracle and DB2 syntax, among others, to allow us to reasonably approximate a running system on

H2, more than anything else, is great for testing. It can emulate oracle and DB2 syntax, among others, to allow us to reasonably approximate a running system on our own machines, then test against the big database (which is much slower) at a later stage. Fully native java and an in-memory implementation mean that we can very quickly implement it in our systems.