A method and system for creating a software application code for building an application comprising multiple Replaceable Self-Contained Components (RSCCs) is disclosed. The method includes creating each RSCC by instantiating and initializing an object instance of a Replaceable Component Class (RCC) that substantially encapsulates construction code of a Self-Contained Component (SCC). A method for creating communication code for allowing necessary collaboration between the RSCCs uses a Service Registration Object (SRO), implements necessary coupling code within the RSCCs that provide services for registering its services with the SRO and implements necessary coupling code within the RSCCs that require services for finding and getting the required services from the SRO. Another method for creating necessary communication code between any two RSCCs includes implementing appropriate coupling interfaces in each of the two RSCCs and implementing necessary communication code in the software application code using the coupling interfaces of the two RSCCs.