The VVM (virtual virtual machine) is a systematic approach to adaptability and reconfigurability for portable, object-oriented applications based on byte-coded languages such as Java and Smalltalk. The main objectives of the VVM are (i) to allow adaptation of language and system according to a particular application domain; (ii) to provide extensibility by allowing a live execution environment to evolve according to new protocols or language standards; and (iii) to provide a common substrate on which to achieve true interoperability between different languages. On the way to implement a VVM we have already implemented VVM1 (and its application to active networks) and VVM2 (and its application to flexible Web cache and distributed observation). The VVM2 is a highly-flexible language kernel which consists of a minimal, complete programming language in which the most important goal is to maximise the amount of reflective access and intercession that are possible, at the lowest possible software level.