When using Java’s Map implementations, it is sometimes common to invoke the Map ‘s get (Object) method and to react differently based on whether the value returned is null or not.

Do you need to know how to sort Java objects in a collection, array, or map? Here's how to use the Comparable and Comparator interfaces and avoid ClassCastExceptions.

HashMap vs. Hashtable similarities Both the Hashtable and HashMap implement the Map interface and both share the same set of methods used to add, remove and manipulate elements of a key-value, ...