Java EnumMap clear() Method

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Description

The Java EnumMap clear() method removes all mappings from this map.

Declaration

Following is the declaration for java.util.EnumMap.clear() method

public void clear()

Parameters

NA

Return Value

This method does not return any value.

Exception

NA

Clearing an EnumMap of Enum, Integer Pairs Example

The following example shows the usage of Java EnumMap clear() method to clear the EnumMap instance. We've created a enum Numbers. Then EnumMap is created of enum Numbers and Integer. Few entries are added and enumMap is printed. Using clear() method, enumMap is cleared and printed again.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,Integer> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, 1);
      map.put(Numbers.TWO, 2);
      map.put(Numbers.THREE,3);
      map.put(Numbers.FOUR, 4);

      // print the whole map
      System.out.println(map); 

      // clear the mappings
      map.clear();

      // print the map again
      System.out.println(map); 
   }
}

Let us compile and run the above program, this will produce the following result −

{ONE=1, TWO=2, THREE=3, FOUR=4}
{}

Clearing an EnumMap of Enum, String Pairs Example

The following example shows the usage of Java EnumMap clear() method to clear the EnumMap instance. We've created a enum Numbers. Then EnumMap is created of enum Numbers and String. Few entries are added and enumMap is printed. Using clear() method, enumMap is cleared and printed again.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,String> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, "1");
      map.put(Numbers.TWO, "2");
      map.put(Numbers.THREE,"3");
      map.put(Numbers.FOUR, "4");

      // print the whole map
      System.out.println(map); 

      // clear the mappings
      map.clear();

      // print the map again
      System.out.println(map); 
   }
}

Let us compile and run the above program, this will produce the following result −

{ONE=1, TWO=2, THREE=3, FOUR=4}
{}

Clearing an EnumMap of Enum, Object Pairs Example

The following example shows the usage of Java EnumMap clear() method to clear the EnumMap instance. We've created a enum Numbers. Then EnumMap is created of enum Numbers and Student objects. Few entries are added and enumMap is printed. Using clear() method, enumMap is cleared and printed again.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,Student> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, new Student(1, "Julie"));
      map.put(Numbers.TWO, new Student(2, "Robert"));
      map.put(Numbers.THREE,new Student(3, "Adam"));
      map.put(Numbers.FOUR, new Student(4, "Jene"));

      // print the whole map
      System.out.println(map); 

      // clear the mappings
      map.clear();

      // print the map again
      System.out.println(map); 
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Let us compile and run the above program, this will produce the following result −

{ONE=[ 1, Julie ], TWO=[ 2, Robert ], THREE=[ 3, Adam ], FOUR=[ 4, Jene ]}
{}