Java Collection, HashMap Exercises: Associate the specified value with the specified key in a HashMap

Java Collection, HashMap Exercises: Exercise-1 with Solution

Write a Java program to associate the specified value with the specified key in a HashMap.

Sample Solution:

Java Code:

import java.util.*;  
public class Example1 {  
  public static void main(String args[]) {  
  HashMap<Integer,String> hash_map= new HashMap<Integer,String>();  
  hash_map.put(1, "Red");
  hash_map.put(2, "Green");
  hash_map.put(3, "Black");
  hash_map.put(4, "White");
  hash_map.put(5, "Blue");
  for(Map.Entry x:hash_map.entrySet()){  
   System.out.println(x.getKey()+" "+x.getValue());  

Sample Output:

1 Red                                                                  
2 Green                                                                
3 Black                                                                
4 White                                                                
5 Blue

Java Code Editor:

Contribute your code and comments through Disqus.

Previous: Change priorityQueue to maximum priorityqueue.
Next: Count the number of key-value (size) mappings in a map.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

Share this Tutorial / Exercise on : Facebook and Twitter

Java: Tips of the Day


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