During software design, we may face the problem that the same abstraction can have multiple implementations. This is mostly visible when doing cross-platform development. Examples could include a line-feed line break on Linux or the existence of a registry on Windows. A Java implementation that needs to get specific system information, by running specific OS calls, will definitely need to be able to vary the implementation. One way to do this is by using inheritance, but this will bind the children to a specific interface, which may not exist on different platforms.
In these cases, it is advisable to use the bridge pattern, since it allows moving away from a proliferation of classes that extend a specific abstraction to nested generalizations, a term coined by Rumbaugh, where we handle the first generalization, and then the other, thus multiplying all the combinations...
