EnumSet copyOf() Method in Java Last Updated : 02 Jul, 2018 Improve Improve Like Article Like Save Share Report The java.util.EnumSet.copyOf(Collection collect) method in Java is used to copy all of the contents from a collection to a new enum set. At first, the collection is made out of the elements of the enum and then a new enum set is created, which is the copy of the collection. Syntax: New_Enum_Set = EnumSet.copyOf(Collection collect) Parameters: The method accepts one parameter collect of the object type of the enum and refers to the collection whose values are to be copied into the New_Enum_Set. Return Values: The method does not return any values. Exceptions: IllegalArgumentException : This exception is thrown if collect is not an EnumSet instance and contains elements that cannot be compared with the enum or contains no element. NullPointerException : This exception is thrown if collect is NULL. Below program illustrates the working of java.util.EnumSet.copyOf() method: // Java program to demonstrate copyOf() method import java.util.*; // Creating an enum of GFG type enum GFG { Welcome, To, The, World, of, Geeks } ; public class Enum_Set_Demo { public static void main(String[] args) { // Creating an empty collection Collection<GFG> collect = new ArrayList<GFG>(); // Adding elements to the Collection collect.add(GFG.Welcome); collect.add(GFG.World); collect.add(GFG.Geeks); // Displaying the collection System.out.println("The collection is: " + collect); EnumSet<GFG> e_set = EnumSet.copyOf(collect); // Displaying the final set System.out.println("The enum set is:" + e_set); } } Output: The collection is: [Welcome, World, Geeks] The enum set is:[Welcome, World, Geeks] The java.util.EnumSet.copyOf(EnumSet e_set) method in Java is used to copy all of the contents from an existing EnumSet i.e., e_set, to a new enum set. Syntax: New_Enum_Set = EnumSet.copyOf(EnumSet e_set) Parameters: The method accepts one parameter e_set of the object type of the enum and refers to the set whose values are to be copied into the New_Enum_Set. Return Values: The method does not return any values. Exceptions: The method throws NullPointerException when e_set is NULL. Below program illustrates the working of java.util.EnumSet.copyOf() method: // Java program to demonstrate copyOf() method import java.util.*; // Creating an enum of CARS type enum CARS { RANGE_ROVER, MUSTANG, CAMARO, AUDI, BMW } ; public class Enum_Set_Demo { public static void main(String[] args) { // Creating an empty EnumSet // Getting all elements from CARS EnumSet<CARS> e_set = EnumSet.allOf(CARS.class); // Displaying the initial EnumSet System.out.println("Initial set is: " + e_set); // Copying the set EnumSet<CARS> new_set = EnumSet.copyOf(e_set); // Displaying the final set System.out.println("The new set is: " + new_set); } } Output: Initial set is: [RANGE_ROVER, MUSTANG, CAMARO, AUDI, BMW] The new set is: [RANGE_ROVER, MUSTANG, CAMARO, AUDI, BMW] Like Article Suggest improvement Previous EnumSet complementOf() Method in Java Next EnumSet noneOf() Method in Java Share your thoughts in the comments Add Your Comment Please Login to comment...