Incomplete library class smell

Software reuse is a real buzzword in the object oriented community. Library classes (for example Java's library) are very important when developing a program and because it is often not possible for developers to change the library classes they are using particular effort has to be put into the development of library classes to ensure that they are complete in terms of the behavior they offer. However, this can be difficult and requires thinking of all possible future uses for code, which conflicts with You ain't gonna need it.