The data structures supplied by the package java.util which are very powerful and performs a wide range of functions. These data structures consist of these interface and classes:
The Enumeration interface defines a way to retrieve the successive elements from a data structure.
The class BitSet implements a group of bits or flags that can be set and cleared individually.
The Stack class implements a last-in-first-out (LIFO in short) stack of elements.
The Vector class is same as a traditional Java array, except that it can grow as necessary to accommodate the new elements.
The Hashtable class provides a means of organizing data based on some user-defined key structure.
The Dictionary class is an abstract class which defines a data structure for mapping keys to values.
Properties is a subclass of the Hashtable, used to maintain the lists of values in which the key and value also is a String