See O-R mapping and object database. There are three major features in object-oriented programming that makes them different than non-OOP languages: encapsulation, inheritance and polymorphism.

For example, RTOSes have threads, semaphores, mutexes, and other objects organized as classes in C, although often without an explicit coding convention, such as the one presented here. [1] Miro Samek ...

Many mistakenly assume that interfaces only sidestep Java’s failure to support multiple implementation inheritance ... are currently touring Java’s object-oriented language basics.

An introduction to the principles of object-oriented programming. It covers both object-oriented programming techniques and their application to program design including classes, objects and objects ...