The original title is about OOP's real essence focusing on state, behavior, and invariants. Let me rewrite this for a mobile feed.

Short summary

This article re-examines OOP beyond the standard four pillars, arguing that objects exist to protect invariants rather than simply store data. It clarifies that encapsulation is about access control and invariant guarantees, not lifecycle management, and that inheritance is a modeling tool rather than a default fix for code duplication. The piece uses Java examples to illustrate how proper OOP design centers on responsibility and state-behavior binding.

• •OOP is about protecting invariants, not just hiding data
• •Encapsulation controls access to state; it is distinct from lifecycle management
• •Inheritance models 'is-a' relationships and should not be the default solution for code duplication

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