32. A data processing system comprising: a computer readable memory having a data structure stored therein, said data structure comprising: a parser for parsing a specification of a computing application for a mobile information device by using a descriptor element factory, said specification being written in an extended markup language and comprising tags of said markup language that correspond to functions of said application to create a descriptor object model comprising objects that implement said functions, wherein the parsing comprises reading different ones of said tags with different readers registered in a factory to be instantiated, and said parser for outputting a plurality of objects according to the descriptor object model, said objects including a project descriptor object; a code generator accepting outputs of said parser that (i) accesses a generation object model according to a specification of a project descriptor object and (ii) dynamically produces source code based on said descriptor object model and said generation object model by using a generation object factory that produces generation objects, said generation objects being operable to generate class files of said source code; and a compiler accepting said source code for compilation into object code, said compiler comprising a generator a verification module for preverifying classes of the class files of said source code; and a packer for packaging said object code into an archive file said packer being configured to include application descriptor information in a manifest of said archive file, said archive file being adapted to be downloaded to and run by the mobile information device.
32. A data processing system comprising: a computer readable memory having a data structure stored therein, said data structure comprising: a parser for parsing a specification of a computing application for a mobile information device by using a descriptor element factory, said specification being written in an extended markup language and comprising tags of said markup language that correspond to functions of said application to create a descriptor object model comprising objects that implement said functions, wherein the parsing comprises reading different ones of said tags with different readers registered in a factory to be instantiated, and said parser for outputting a plurality of objects according to the descriptor object model, said objects including a project descriptor object; a code generator accepting outputs of said parser that (i) accesses a generation object model according to a specification of a project descriptor object and (ii) dynamically produces source code based on said descriptor object model and said generation object model by using a generation object factory that produces generation objects, said generation objects being operable to generate class files of said source code; and a compiler accepting said source code for compilation into object code, said compiler comprising a generator a verification module for preverifying classes of the class files of said source code; and a packer for packaging said object code into an archive file said packer being configured to include application descriptor information in a manifest of said archive file, said archive file being adapted to be downloaded to and run by the mobile information device. 40. The data processing system according to claim 32 , wherein said data structure further comprises a subprogram for verifying said specification of said computing application against schema definitions of said markup language.