Stage 2 · Lesson 2 of 8
Encapsulation
means an object keeps its data private. Other code can only use the operations the object offers, and those operations keep the data valid. Think of a bank account.
It should offer deposit and withdraw, and withdraw can refuse to go overdrawn. It should not have a public balance field that anyone can set to a negative number. This protects : rules that must always be true, such as "the balance is never below zero".
It also lets you change how a class works inside without breaking the code that uses it. Encapsulation is the first of the four pillars of and the one that matters most day to day.
Common trapmaking every field private and then adding a and for each one, which exposes the data anyway.
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Resources for this stage
Start with· follow one of these
- CoursePaidGrokking SOLID Design Principles
Design Gurus · Beginner · $50 one-time
Each SOLID principle with a broken example and its fix, at a beginner-friendly pace
- CourseFreeJava Programming MOOC
University of Helsinki · Beginner
Free, exercise-heavy course whose second half is a thorough, tested introduction to OOP