1. A computer system comprising a processor and a computer readable memory unit coupled to the processor, said memory unit containing computer readable software code configured to be executed by the processor to implement a method for providing a maintenance environment for computer program code, said method comprising: exporting a software application program to an external file, wherein the computer program code comprises the software application program, wherein the software application program in the external file comprises a plurality of statement group keywords, wherein each statement group keyword represents a different statement group comprising a group of statements in the software application program in the external file, and wherein the external file is an External Source Format (ESF) file which is a serial file consisting of 80-byte fixed length records; after said exporting, storing a statement group name of each statement group in a statement group names list file and copying each statement group to a different statement group file whose name is the statement group name of the statement group being copied, wherein each statement group name in the statement group names list file is associated with a corresponding statement group file resulting from said copying each statement group to a different statement group file; and after said storing the statement group name of each statement group and said copying each statement group to the different statement group file, placing a link in the statement group names list file for each statement group name therein to provide an independent association and a navigation route between each statement group name in the statement group names list file and its associated statement group file.