public class WeakIdentityHashMap
Implements a combination of WeakHashMap and IdentityHashMap.
Useful for caches that need to key off of a == comparison
instead of a .equals.
This class is not a general-purpose Map implementation! While
this class implements the Map interface, it intentionally violates
Map's general contract, which mandates the use of the equals method
when comparing objects. This class is designed for use only in the
rare cases wherein reference-equality semantics are required.
Note that this implementation is not synchronized.