Immutable Object

An object whose data cannot change after it is created.

What is Immutable Object?

An immutable object cannot change after it is created. To "change" it, you make a new object with the new values. Strings in C#, Java and Python work this way.

public record Point(int X, int Y);

var a = new Point(1, 2);
var b = a with { X = 5 }; // a is unchanged; b is a new Point(5, 2)

Level: Journeyman · More OOP terms at this level

Updated September 27, 2026