There are several alternative implementations and completion of the Ruby language as of 2008 including JRuby, Rubinius, IronRuby and YARV. Each of them has different approach especially that JRuby provides just-in-time compilation functionality. JIT or just-in-time compilation is also known as Dynamic Translation. In computing, it is a system and a technique for improving runtime performance of a computer program. It has two earlier ideas in run-time environments such as dynamic compilation and bytecode compilation. Its advantage over statically compiling the code at development time is that it can recompile the code and its ability to enforce security guarantees. Hence it can merge a few of the advantages of interpretation and static compilation.