10 Example of Hashtable in Java – Java Hashtable Tutorial

http://javarevisited.blogspot.com/2012/01/java-hashtable-example-tutorial-code.html

import java.util.Collection;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.Set;

publicclass HashtableDemo {

publicstaticvoid main(String args[]) {

// Creating Hashtable for example

Hashtable companies = new Hashtable();

// Java Hashtable example to put object into Hashtable

// put(key, value) is used to insert object into map

companies.put( "Google" , "United States" );

companies.put( "Nokia" , "Finland" );

companies.put( "Sony" , "Japan" );

// Java Hashtable example to get Object from Hashtable

// get(key) method is used to retrieve Objects from Hashtable

companies.get( "Google" );

// Hashtable containsKey Example

// Use containsKey(Object) method to check if an Object exits as key in

// hashtable

System. out .println( "Does hashtable contains Google as key: "

+ companies.containsKey( "Google" ));

// Hashtable containsValue Example

// just like containsKey(), containsValue returns true if hashtable

// contains specified object as value

System. out .println( "Does hashtable contains Japan as value: "

+ companies.containsValue( "Japan" ));

// Hashtable enumeration Example

// hashtabl.elements() return enumeration of all hashtable values

Enumeration enumeration = companies.elements();

while (enumeration.hasMoreElements()) {

System. out

.println( "hashtable values: " + enumeration.nextElement());

}

// How to check if Hashtable is empty in Java

// use isEmpty method of hashtable to check emptiness of hashtable in

// Java

System. out .println( "Is companies hashtable empty: "

+ companies.isEmpty());

// How to find size of Hashtable in Java

// use hashtable.size() method to find size of hashtable in Java

System. out .println( "Size of hashtable in Java: " + companies.size());

// How to get all values form hashtable in Java

// you can use keySet() method to get a Set of all the keys of hashtable

// in Java

Set hashtableKeys = companies.keySet();

// you can also get enumeration of all keys by using method keys()

Enumeration hashtableKeysEnum = companies.keys();

// How to get all keys from hashtable in Java

// There are two ways to get all values form hashtalbe first by using

// Enumeration and second getting values ad Collection

Enumeration hashtableValuesEnum = companies.elements();

Collection hashtableValues = companies.values();

// Hashtable clear example

// by using clear() we can reuse an existing hashtable, it clears all

// mappings.

companies.clear();

}

}

Output:

Does hashtable contains Google as key: true

Does hashtable contains Japan as value: true

hashtable values: Finland

hashtable values: United States

hashtable values: Japan

Is companies hashtable empty: false

Size of hashtable in Java: 3

Read more: http://javarevisited.blogspot.com/2012/01/java-hashtable-example-tutorial-code.html#ixzz3Jd7e8SSF