TreeMap V get(Object key) Method Example Program


Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
More formally, if this map contains a mapping from a key k to a value v such that key compares equal to k according to the map's ordering, then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

Program

package com.candidjava;

import java.util.TreeMap;

/**
 * @author: Hari Haran
 * @discription:The get(Object key) method is used to return the value to which
 *                  the specified key is mapped, or null if this map contains no
 *                  mapping for the key.
 */

public class TreeMapGet {
	public static void main(String[] args) {
		TreeMap<Integer, String> tm = new TreeMap<Integer, String>();

		tm.put(1, "Anand");
		tm.put(2, "Hari Haran");
		tm.put(8, "Kamal");
		tm.put(4, "Karthikeyan");
		tm.put(5, "Mohan");
		tm.put(6, "Vinoth");
		tm.put(7, "Hari Haran");

		System.out.println("Checking value for key 3");
		System.out.println("Value is: " + tm.get(3));
	}
}

Output

Checking value for key 3
Value is: null

Explanation

public V get(Object key)
Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
More formally, if this map contains a mapping from a key k to a value v such that key compares equal to k according to the map's ordering, then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

Specified by:
get in interface Map<K,V>
Overrides:
get in class AbstractMap<K,V>
Parameters:
key - the key whose associated value is to be returned
Returns:
the value to which the specified key is mapped, or null if this map contains no mapping for the key
Throws:
ClassCastException - if the specified key cannot be compared with the keys currently in the map
NullPointerException - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys


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