Lesson 22: Records (Java 16+)

Records are compact, immutable data carriers — the compiler auto-generates constructor, getters, equals, hashCode, and toString.

Real-time example

An API response for GeoPoint(lat, lng) needs no boilerplate — one line replaces what used to be 30+ lines of a POJO.

record GeoPoint(double lat, double lng) {}

GeoPoint delhi = new GeoPoint(28.6139, 77.2090);
System.out.println(delhi.lat());   // 28.6139
System.out.println(delhi);         // GeoPoint[lat=28.6139, lng=77.209]

What's happening

Records are implicitly final and immutable — once created, delhi can never change, which is ideal for value objects like coordinates.

Use records for pure data (DTOs, API payloads, coordinates); use classes when you need mutable state or inheritance.