JIT allows a range of optimisations that are not possible with AOT compilation. A JIT has access to more information at runtime such as profiling data and so ca

JIT allows a range of optimisations that are not possible with AOT compilation. A JIT has access to more information at runtime such as profiling data and so can perform more informed optimisations. It can also change over the lifetime of the programme if observations change. Some interesting stuff here http://wikis.sun.com/display/HotSpotInternals/PerformanceTechniques http://wikis.sun.com/display/HotSpotInternals/PerformanceTec...