JRuby is an implementation of the Ruby programming language that runs in the Java Virtual Machine (JVM).
As Ruby and Ruby on Rails become more popular, JRuby becomes an interesting technology to leverage the portability, security, and class libraries of the JVM while using Ruby features like simple syntax and closures.
If you're writing a small application that needs a relational database, or you want to be able to ship a database with your product, then the Derby database is an excellent choice for a persistence mechanism. This tutorial shows you two methods of connecting to and building Derby database applications from JRuby.
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