In computer science, cloning refers to the making of an exact copy of an object, frequently under the paradigm of instance-based programming, or object-oriented programming (OOP). In computer science, cloning refers to the making of an exact copy of an object, frequently under the paradigm of instance-based programming, or object-oriented programming (OOP). In most programming languages (exceptions include: Ruby), primitive types such as double, float, int, long, etc. simply store their values somewhere in the computer's memory (often the call stack). By using simple assignment, you can copy the contents of the variable to another one: