Defining Just-in-time compilation

Just-in-time compilation is a feature shared by Java and .Net Framework and can increase the runtime performance for computer programs. Just-in-time compilation is also referred to as dynamic compilation and has advantages in portability, flexibility, and performance. Just-In-Time compilation does however have a delay in startup time but is still a great feature to have when dealing with large blocks of repeated code.

Just-in-time compilation helps to improve runtime performance by caching blocks of code for reuse. Unlike interpreted languages that have to compile programs line by line, operand by operand. Just-in-time compilation stores blocks of code that are compiled so that if another block of code like the original occurs again, the compiler can use the already generated code instead. This helps to gave runtime performance and is often used in Java.

Just-in-time compilation is a form of dynamic compilation which compiles code in the first few moments/minutes of runtime execution. Though there is an initial delay involved, it helps to improve performance overall.

Just-in-time compilation is a useful feature to have when dealing with large programs that can be improved by runtime compilation. The improvement in speed comes from the reuse of code and is a great tool to have. Due to the improvement of performance, just-in-time compilation will undoubtedly become more important in the future.

Resources: http://en.wikipedia.org/wiki/Just-in-time_compilation
among other Wikipedia articles.