Java: Get all keys from the given a Tree Map

Last update on May 23 2025 13:08:51 (UTC/GMT +8 hours)

5. Get All Keys from TreeMap

Write a Java program to get all keys from a Tree Map.

Sample Solution:-

Java Code:

import java.util.*;  
public class Example5 {  
   public static void main(String args[]){  
   // Create a tree map
   TreeMap<String,String> tree_map1=new TreeMap<String,String>();      
   // Put elements to the map 
  tree_map1.put("C1", "Red");
  tree_map1.put("C2", "Green");
  tree_map1.put("C3", "Black");
  tree_map1.put("C4", "White"); 
    
 Set<String> keys = tree_map1.keySet();
        for(String key: keys){
            System.out.println(key);
        }
    }
}

Sample Output:

C1                                                                     
C2                                                                     
C3                                                                     
C4

For more Practice: Solve these Related Problems:

• Write a Java program to extract all keys from a TreeMap using keySet() and print them.
• Write a Java program to convert a TreeMap’s key set to an ArrayList and then sort it in reverse order.
• Write a Java program to use Java streams to filter the keys of a TreeMap based on a custom predicate.
• Write a Java program to iterate over the keys of a TreeMap and count how many start with a specified character.

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