1. A computer-implemented method of debugging an object-oriented computer program, the method comprising: (a) in response to user input, setting an inheritance breakpoint that is associated with a first program entity in the object-oriented computer program in which is identified a method; and (b) halting execution of the object-oriented computer program during debugging in response to reaching an implementation of the method defined in a second program entity in the object-oriented computer program that is different from the first program entity.