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Java Collection, TreeMap Exercises: Get all keys from the given a Tree Map

Java Collection, TreeMap Exercises: Exercise-5 with Solution

Write a Java program to get all keys from the given 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

Java Code Editor:

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Java: Tips of the Day

getEnumMap

Converts to enum to Map where key is the name and value is Enum itself. 

public static <E extends Enum<E>> Map<String, E> getEnumMap(final Class<E> enumClass) {
    return Arrays.stream(enumClass.getEnumConstants())
            .collect(Collectors.toMap(Enum::name, Function.identity()));
}

Ref: https://bit.ly/3xXcFZt