Thursday, August 28, 2025
HomeLanguagesJavaTreeMap containsKey() Method in Java

TreeMap containsKey() Method in Java

The java.util.TreeMap.containsKey() method is used to check whether a particular key is being mapped in the TreeMap or not. It takes the key element as a parameter and returns True if that element is mapped in the map.

Syntax:

Tree_Map.containsKey(key_element)

Parameters: The method takes just one parameter key_element that refers to the key whose mapping is supposed to be checked inside a map.

Return Value: The method returns boolean true if the presence of the key is detected else false .

Below programs are used to illustrate the working of java.util.TreeMap.containsKey() Method:
Program 1: Mapping String Values to Integer Keys.




// Java code to illustrate the containsKey() method
import java.util.*;
  
public class Tree_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty TreeMap
        TreeMap<Integer, String> tree_map = 
        new TreeMap<Integer, String>();
  
        // Mapping string values to int keys
        tree_map.put(10, "Geeks");
        tree_map.put(15, "4");
        tree_map.put(20, "Geeks");
        tree_map.put(25, "Welcomes");
        tree_map.put(30, "You");
  
        // Displaying the TreeMap
        System.out.println("Initial Mappings are: " + tree_map);
  
        // Checking for the key_element '20'
        System.out.println("Is the key '20' present? "
        tree_map.containsKey(20));
  
        // Checking for the key_element '5'
        System.out.println("Is the key '5' present? "
        tree_map.containsKey(5));
    }
}


Output:

Initial Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You}
Is the key '20' present? true
Is the key '5' present? false

Program 2: Mapping Integer Values to String Keys.




// Java code to illustrate the containsKey() method
import java.util.*;
  
public class Tree_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty TreeMap
        TreeMap<String, Integer> tree_map = 
        new TreeMap<String, Integer>();
  
        // Mapping int values to string keys
        tree_map.put("Geeks", 10);
        tree_map.put("4", 15);
        tree_map.put("Geeks", 20);
        tree_map.put("Welcomes", 25);
        tree_map.put("You", 30);
  
        // Displaying the TreeMap
        System.out.println("Initial Mappings are: " + tree_map);
  
        // Checking for the key_element 'Welcomes'
        System.out.println("Is the key 'Welcomes' present? "
        tree_map.containsKey("Welcomes"));
  
        // Checking for the key_element 'World'
        System.out.println("Is the key 'World' present? "
        tree_map.containsKey("World"));
    }
}


Output:

Initial Mappings are: {4=15, Geeks=20, Welcomes=25, You=30}
Is the key 'Welcomes' present? true
Is the key 'World' present? false

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

RELATED ARTICLES

Most Popular

Dominic
32236 POSTS0 COMMENTS
Milvus
80 POSTS0 COMMENTS
Nango Kala
6609 POSTS0 COMMENTS
Nicole Veronica
11779 POSTS0 COMMENTS
Nokonwaba Nkukhwana
11828 POSTS0 COMMENTS
Shaida Kate Naidoo
6719 POSTS0 COMMENTS
Ted Musemwa
7002 POSTS0 COMMENTS
Thapelo Manthata
6678 POSTS0 COMMENTS
Umr Jansen
6690 POSTS0 COMMENTS