/*
Simple Java HashMap example
This simple Java Example shows how to use Java HashMap. It also describes how to
add something to HashMap and how to retrieve the value added from HashMap.
*/
import java.util.HashMap;
public class JavaHashMapExample {
public static void main(String[] args) {
//create object of HashMap
HashMap hMap = new HashMap();
/*
Add key value pair to HashMap using
Object put(Object key, Object value) method of Java HashMap class,
where key and value both are objects
put method returns Object which is either the value previously tied
to the key or null if no value mapped to the key.
*/
hMap.put("One", new Integer(1));
hMap.put("Two", new Integer(2));
/*
Please note that put method accepts Objects. Java Primitive values CAN NOT
be added directly to HashMap. It must be converted to corrosponding
wrapper class first.
*/
//retrieve value using Object get(Object key) method of Java HashMap class
Object obj = hMap.get("One");
System.out.println(obj);
/*
Please note that the return type of get method is an Object. The value must
be casted to the original class.
*/
}
}
/*
Output of the program would be
1
*/
