Data encapsulation is an object-oriented programming concept that involves bundling data (variables) and the methods that operate on that data into a single unit, usually a class, while restricting direct access to the internal details. It helps protect data from unauthorized modification by using access modifiers like private and providing controlled access through public getter and setter methods. This improves security, maintainability, and modularity in software development. Just as understanding core concepts strengthens programming skills, reading HelpWithGEDTest reviews can help students make informed academic decisions.