A method of supplying program units of a computer program as the program needs the program units includes running a program skeleton. The program skeleton is derived from the program, but has a program stub where a program unit associated with the program stub may be inserted. Upon encountering the program stub, the method includes getting the program unit associated with the program stub and inserting the program unit at the program stub. A method of supplying funclets of a computer program from a server computer system to a client computer system includes receiving a plurality of requests for funclets during a test period. If a tested probability of requests for a first funclet being followed by requests for a second funclet is at least a predetermined probability, then the method also includes sending the first funclet and the second funclet to the client computer system in response to a request from the client computer system for the first funclet after the test period.