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Java Collection, HashMap Exercises: Remove all the mappings from a map

Java Collection, HashMap Exercises: Exercise-4 with Solution

Write a Java program to remove all the mappings from a map.

Sample Solution:-

Java Code:

import java.util.*;  
public class Example4 {  
   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");
  // print the map
  System.out.println("The Original linked map: " + hash_map);
  // Removing all the elements from the linked map
  hash_map.clear();
  System.out.println("The New map: " + hash_map);
 }
}

Sample Output:

The Original linked map: {1=Red, 2=Green, 3=Black, 4=White, 5=Blue}    
The New map: {}

Java Code Editor:

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Previous: Copy all of the mappings from the specified map to another map.
Next: Check whether a map contains key-value mappings (empty) or not.

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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