Java: Get a key-value mapping associated with the least key greater than or equal to the given key

Last update on May 23 2025 13:08:03 (UTC/GMT +8 hours)

25. Get Mapping with Ceiling Key

Write a Java program to get a key-value mapping associated with the least key greater than or equal to the given key. Return null if there is no such key.

Sample Solution:-

Java Code:

import java.util.*;
import java.util.Map.Entry;  
public class Example25 {  
           public static void main(String args[]) {
  // Declare tree maps
  TreeMap < Integer, String > tree_map = new TreeMap < Integer, String > ();
  // Put elements to the map 
  tree_map.put(10, "Red");
  tree_map.put(20, "Green");
  tree_map.put(30, "Black");
  tree_map.put(40, "White");
  tree_map.put(50, "Pink");
  System.out.println("Orginal TreeMap content: " + tree_map);
  System.out.println("Keys greater than or equal to 20: " + tree_map.ceilingEntry(20));
  System.out.println("Keys greater than or equal to 40: " + tree_map.ceilingEntry(40));
  System.out.println("Keys greater than or equal to 50: " + tree_map.ceilingEntry(50));
 }
}

Sample Output:

Orginal TreeMap content: {10=Red, 20=Green, 30=Black, 40=White, 50=Pink
}                                                                      
Keys greater than or equal to 20: 20=Green                             
Keys greater than or equal to 40: 40=White                             
Keys greater than or equal to 50: 50=Pink

For more Practice: Solve these Related Problems:

Write a Java program to use ceilingEntry() on a TreeMap to retrieve the mapping with the least key greater than or equal to a specified key.
Write a Java program to implement a lambda expression that returns the entry for the least key ≥ a given value using ceilingEntry().
Write a Java program to handle null returns from ceilingEntry() by providing a default mapping.
Write a Java program to compare the output of ceilingEntry() with a manual search through the TreeMap’s key set.

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Java Code Editor:

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