equals

open operator override fun equals(other: Any?): Boolean

Indicates whether some other object is "equal to" this one. Implementations must fulfil the following requirements:

Reflexive: for any non-null value x, x.equals(x) should return true.
Symmetric: for any non-null values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
Transitive: for any non-null values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
Consistent: for any non-null values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
Never equal to null: for any non-null value x, x.equals(null) should return false.