Encapsulation & Cohesion

OOPsTopic 2 of 92 questions

Q1Why does returning a live collection break encapsulation?

Private field plus getter returning the live collection is fake encapsulation. The caller mutates internals via the reference. Fix: return Collections.unmodifiableList() or a defensive copy or List.copyOf().

Read Answer

Q2What is cohesion and why is high cohesion a design goal?

High cohesion means one class, one purpose, all methods related (SRP). Low cohesion means a God class doing many unrelated things. The goal: high cohesion plus loose coupling equals clean design.

Read Answer