Re:JavaScript: The Curious Case of null >= 0
by kbp on Saturday September 09, 2017 @01:16PM
(#15207992)
> Java has (or had?) a similar issue with comparing boxed Ints -- equality checks for object level equality while inequality compares the values.
In Java 5 and up, 'new Integer(1) < new Integer(2)' will return true, because it automatically unboxes both Integers and compares them as primitives (before Java 5 it was a compile error).
It will not unbox the Integers in 'new Integer(1) == new Integer(1)', though, because given objects, '==' is always reference equality, so it will return false because they're different instances ('!=' would still return true, though). To compare objects by value, you use equals; 'new Integer(1).equals(new Integer(1))' is true.
Without explicit casting, the equality operator casts to a more general type (or rather, doesn't cast at all) than the inequality operator (which casts to numerics).
This happens anywhere you have weird coercion rules.