Methods and apparatus implementing a technique for adding an interface to a boss object at run-time. A boss object includes one or more interfaces and each interface has a corresponding implementation class. In general, in one aspect, the technique includes: reading a first boss class having a first interface, defined in a first software component; reading a second interface, defined in a separate second software component; and binding the second interface to the first boss class, so that instantiating the first boss class creates a first boss object including the first interface and the second interface.