java.util.TreeMap.higherKey() Method


ThehigherKey(K key) method is used to return the least key strictly greater than the given key, or null if there is no such key.


Following is the declaration for java.util.TreeMap.higherKey() method.

public K higherKey(K key)


key − This is the key to be matched.

Return Value

The method call returns the least key greater than key, or null if there is no such key.


  • ClassCastException − This exception is thrown if the specified key cannot be compared with the keys currently in the map.

  • NullPointerException − This exception is thrown if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys.


The following example shows the usage of java.util.TreeMap.higherKey() method.

package com.tutorialspoint;

import java.util.*;

public class TreeMapDemo {
   public static void main(String[] args) {

      // creating tree map 
      TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();

      // populating tree map
      treemap.put(2, "two");
      treemap.put(1, "one");
      treemap.put(3, "three");
      treemap.put(6, "six");
      treemap.put(5, "five");

      // getting higher key for key 4          
      System.out.println("Checking values of the map");
      System.out.println("Value is: "+ treemap.higherKey(3));

Let us compile and run the above program, this will produce the following result.

Checking values of the map
Value is: 5
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