Before we get into the details of ARC, we need to rewind the time machine to a previous epoch. The year is 1988, and Objective-C is licensed by NeXT and starting to make its way into their operating system. In 1996, Apple acquires NeXT, alongside the release of OS X, a new and modern toolchain based on Objective-C. Objective-C is a strict superset of C, which means that any valid C code is valid Objective-C code, but unlike C, Objective-C has a modern and efficient memory management engine, based on reference counting.
Reference counting is a technique that accounts for the exact number of references to a particular object that exist at any given time in the memory. Once there are no references, an object, it is deallocated. This is a very different memory management technique, as compared to garbage collection, which you can find in Java...
