Java The Dictionary Class


Dictionary is an abstract class that represents a key/value storage repository and operates much like Map.

Given a key and value, you can store the value in a Dictionary object. Once the value is stored, you can retrieve it by using its key. Thus, like a map, a dictionary can be thought of as a list of key/value pairs.

The abstract methods defined by Dictionary are listed below −

Sr.No.Method & Description

Enumeration elements( )

Returns an enumeration of the values contained in the dictionary.


Object get(Object key)

Returns the object that contains the value associated with the key. If the key is not in the dictionary, a null object is returned.


boolean isEmpty( )

Returns true if the dictionary is empty, and returns false if it contains at least one key.


Enumeration keys( )

Returns an enumeration of the keys contained in the dictionary.


Object put(Object key, Object value)

Inserts a key and its value into the dictionary. Returns null if the key is not already in the dictionary; returns the previous value associated with the key if the key is already in the dictionary.


Object remove(Object key)

Removes the key and its value. Returns the value associated with the key. If the key is not in the dictionary, a null is returned.


int size( )

Returns the number of entries in the dictionary.

The Dictionary class is obsolete. You should implement the Map interface to obtain key/value storage functionality.

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