EnumSet : of(E first, E... rest)

public static <E extends Enum<E>> EnumSet<E> of(E first, E... rest)

Creates an enum set initially containing the specified elements. It uses varargs, so arbitrary number of arguments can be passed. It is likely to run slower than the overloadings that do not use varargs.

import java.util.*;

class EnumSetOfVararg{
 enum Day{
  MON,TUE,WED,THU,
  FRI,SAT,SUN;
 }
 
 public static void main(String args[]){  
  EnumSet<Day> mySet1;
  mySet1 = EnumSet.of(Day.SUN,Day.MON,Day.TUE, Day.WED, Day.THU, Day.FRI);
  
  System.out.println("Elements in mySet1 are");
  System.out.println(mySet1);
 }
}

Output

Elements in mySet1 are
[MON, TUE, WED, THU, FRI, SUN]

1. throws NullPointerException if any of the specified elements are null

import java.util.*;

class EnumSetOfVarargNull{
 enum Day{
  MON,TUE,WED,THU,
  FRI,SAT,SUN;
 }
 
 public static void main(String args[]){  
  EnumSet<Day> mySet1;
  mySet1 = EnumSet.of(Day.SUN,Day.MON,Day.TUE, Day.WED, Day.THU,null);
  
  System.out.println("Elements in mySet1 are");
  System.out.println(mySet1);
 }
}

Output

Exception in thread "main" java.lang.NullPointerException
        at java.util.EnumSet.typeCheck(EnumSet.java:378)
        at java.util.RegularEnumSet.add(RegularEnumSet.java:160)
        at java.util.RegularEnumSet.add(RegularEnumSet.java:36)
        at java.util.EnumSet.of(EnumSet.java:325)
        at EnumSetOfVarargNull.main(EnumSetOfVarargNull.java:11)

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