Java TreeMap.ceilingEntry(K key) example

In this java tutorial, You will learn how to use ceilingEntry(K key) method of TreeMap class.The ceilingEntry(K key) method is used to return a key-value mapping associated with the least key greater than or equal to the given key, or null if there is no such key.

Returns a key-value mapping associated with the least key greater than or equal to the given key, or null if there is no such key.

syntax

public Map.Entry<K,V> ceilingEntry(K key)

Parameters

key - the key

Returns

An entry with the least key greater than or equal to key, or null if there is no such 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.

Java TreeMap ceilingEntry(K key) example

  • Create TreeMap instance new TreeMap < Integer, String > ();
  • Add some few elements in TreeMap e.g. students.put(1, "Pooja");
  • Print the TreeMap value.
  • students.ceilingEntry(2); It will return an entry with the least key greater than or equal to key 2.
  • students.ceilingEntry(5); It will return an entry with the least key greater than or equal to key 5.
package com.technicalkeeda;

import java.util.TreeMap;

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

        TreeMap < Integer, String > students = new TreeMap < Integer, String > ();

        students.put(1, "Pooja");
        students.put(2, "Ajit");
        students.put(3, "Yashwant");
        students.put(4, "Aditi");
        students.put(8, "Mahesh");

        System.out.println("TreeMap values :- " + students);

        System.out.println("Ceiling key entry for key 2:- " + students.ceilingEntry(2));
        System.out.println("Ceiling key entry for key 5:- " + students.ceilingEntry(5));

    }
}

output

TreeMap values :- {1=Pooja, 2=Ajit, 3=Yashwant, 4=Aditi, 8=Mahesh}
Ceiling key entry for key 2:- 2=Ajit
Ceiling key entry for key 5:- 8=Mahesh