Java’s equals() and hashcode() are two methods that work together to verify if two objects have the same value. You can use them to make object comparisons easy and efficient in your Java programs.

The HashMap tutorial also includes some useful code snippets that help developers understand what's going on with a Java HashMap under the covers. For example, the following code used in the tutorial ...

Bug 6321873 explains that the hash code returned by System.identityHashCode(Object) is not guaranteed to be unique (it’s a hash code after all). That being stated, there are situations in which ...