1. An information processing apparatus, comprising: a storage device that stores: a component class library having a plurality of component classes, an application program main body, and a customization mechanism; and a processor that executes the application program main body and the customization mechanism, the customization mechanism comprising a set of processor executable instructions for: registering in a memory, in accordance with a request from the application program main body, first setting information representing a relationship between a first component interface, of a plurality of component interfaces, to initiate a first component class, and a customization point where the first component interface is described in the application program main body; registering in the memory, in accordance with a request from the component class library, second setting information representing a relationship between each of the plurality of component interfaces stored in the component class library and all component classes belonging to each respective component interface; generating an instance for a customization point by executing a component class selected by a user, the component class selected from component classes belonging to the plurality of component interfaces that correspond to the first component interface described at the customization point; embedding the instance generated for the customization point at the customization point in the application program main body; and executing the application program main body with the instance embedded in the application program main body.