java.time.LocalDateTime, are value-based. Instances of a
toString which are computed
solely from the instance's state and not from its identity or the state
of any other object or variable;
==) between instances, identity hash code of
instances, or synchronization on an instances's intrinsic lock;
based on reference equality (
y that are equal
equals() in any computation or method
invocation should produce no visible change in behavior.
A program may produce unpredictable results if it attempts to distinguish two references to equal values of a value-based class, whether directly via reference equality or indirectly via an appeal to synchronization, identity hashing, serialization, or any other identity-sensitive mechanism. Use of such identity-sensitive operations on instances of value-based classes may have unpredictable effects and should be avoided.