1. A method for automatic generation of schema mapping application code, including: loading a code generation tool with source and target schemas, wherein the code generation tool is triggered by selecting a code generation menu item, the code generation menu allowing the user to control aspects of the code generation process including: specifying a file system directory where generated files will be saved, turning off generation of particular application implementation files, defining the mapping specification between the source and the target, and customizing the generated application by incorporating the generated code into the existing application of the user; wherein the code generation tool is configured to generate at least, one of, (i) a stand- alone application, (ii) a web service implementation, and (iii) a software component for performing the specified map transformation from input data documents to produce the output data documents; triggering the code generation tool, wherein the code generation tool is configured to generate an application for generating code for performing the specified map transformation from input data documents to produce the output data documents; wherein the application includes a plurality of static library classes and a plurality of dynamic classes, the implementation of the static library classes being fixed and not dependent upon the source or target schema and map specification for any particular generated application, the implementation and quantity of the dynamic classes being dependent upon the source and target schemas and the map specification that the code generation tool generates; wherein the dynamic classes are separated into two groups, (a) the first group termed the singleton dynamic classes, the first group being dynamic classes for which the code generation tool is invoked once to produce a single version of these classes and, (b) the second group termed the map-specific dynamic classes, the second group being the dynamic classes for which the code generation tool is invoked multiple times to produce various versions of these classes; compiling the code generated by the code generation tool; and executing the code generated by the code generation tool to transform input data files.