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The enumeration() method of java.util.Collections class is used to return an enumeration over the specified collection. This provides interoperability with legacy APIs that require an enumeration as input.
Syntax:

public static  Enumeration enumeration(Collection c)

Parameters: This method takes the collection c as a parameter for which an enumeration is to be returned.
Return Value: This method returns an enumeration over the specified collection.
Below are the examples to illustrate the enumeration() method
Example 1:

Java

// Java program to demonstrate
// enumeration() method
// for String value

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // creating object of List<String>
            List<String> arrlist = new ArrayList<String>();

            // Adding element to srclst
            arrlist.add("Ram");
            arrlist.add("Gopal");
            arrlist.add("Verma");

            // Print the list
            System.out.println("List: " + arrlist);

            // creating object of type Enumeration<String>
            Enumeration<String> e = Collections.enumeration(arrlist);

            // Print the Enumeration
            System.out.println("\nEnumeration over list: ");

            // print the enumeration
            while (e.hasMoreElements())
                System.out.println("Value is: " + e.nextElement());
        }

        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }

        catch (NoSuchElementException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

List: [Ram, Gopal, Verma]

Enumeration over list: 
Value is: Ram
Value is: Gopal
Value is: Verma

Example 2:

Java

// Java program to demonstrate
// enumeration() method
// for Integer value

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // creating object of List<Integer>
            List<Integer> arrlist = new ArrayList<Integer>();

            // Adding element to srclst
            arrlist.add(20);
            arrlist.add(30);
            arrlist.add(40);

            // Print the list
            System.out.println("List: " + arrlist);

            // creating object of type Enumeration<Integer>
            Enumeration<Integer> e = Collections.enumeration(arrlist);

            // Print the Enumeration
            System.out.println("\nEnumeration over list: ");

            // print the enumeration
            while (e.hasMoreElements())
                System.out.println("Value is: " + e.nextElement());
        }

        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }

        catch (NoSuchElementException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

List: [20, 30, 40]

Enumeration over list: 
Value is: 20
Value is: 30
Value is: 40

Collections enumeration() method in Java with Examples

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