Java Utility Library

Java EnumMap - keySet() Method

The java.util.EnumMap.keySet() method returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa.

Syntax

public Set<K> keySet()

Here, K is the type of key maintained by the container.

Parameters

No parameter is required.

Return Value

Returns a set view of the keys contained in this enum map.

Exception

Example:

In the example below, the java.util.EnumMap.keySet() method returns a set view of the keys contained in the given EnumMap.

import java.util.*;

public class MyClass {
  
  //creating an enum
  public enum weekday{
    MON, TUE, WED, THU, FRI
  }

  public static void main(String[] args) {
    //creating EnumMap
    EnumMap<weekday,Integer> MyMap = 
        new EnumMap<weekday,Integer>(weekday.class);

    //associate values in MyMap
    MyMap.put(weekday.MON, 1);
    MyMap.put(weekday.TUE, 2);
    MyMap.put(weekday.WED, 3);
    MyMap.put(weekday.THU, 4);
    MyMap.put(weekday.FRI, 5);

    //printing the content of the map
    System.out.println("MyMap contains: " + MyMap);

    //creating a set view of keys of the map
    Set SetView = MyMap.keySet();

    //printing the set view of keys
    System.out.println("SetView contains: " + SetView);
  }
}

The output of the above code will be:

MyMap contains: {MON=1, TUE=2, WED=3, THU=4, FRI=5}
SetView contains: [MON, TUE, WED, THU, FRI]

❮ Java.util - EnumMap