Which of the following is NOT one of the four main principles of OOP?

The principle that is not one of the four main concepts of Object-Oriented Programming (OOP) is compilation. The four main principles of OOP are encapsulation, abstraction, inheritance, and polymorphism.

Encapsulation refers to the bundling of data (attributes) and methods (functions) that operate on that data within a single unit, typically a class. This principle helps to protect the internal state of an object from unintended interference and misuse by restricting access to certain components.

Abstraction involves simplifying complex reality by modeling classes based on the essential qualities of an object while hiding the unnecessary details. This makes it easier to manage complexity by focusing on what an object does instead of how it does it.

Polymorphism allows objects to be treated as instances of their parent class, even if they belong to different subclasses. This enables a single function or method to work in different ways depending on the object it is operating on, enhancing flexibility and integration within the code.

In contrast, compilation is a process that translates source code written in a programming language into machine code or bytecode. While compilation is a crucial part of the software development process, it is not a principle that defines the structure and behavior of object-oriented programming.