Java Collections enumeration() Method

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Description

The Java Collections enumeration(Collection<T>) method is used to get an enumeration over the specified collection.

Declaration

Following is the declaration for java.util.Collections.enumeration() method.

 
public static <T> Enumeration<T> enumeration(Collection<T> c)

Parameters

c − This is the collection for which an enumeration is to be returned.

Return Value

The method call returns an enumeration over the specified collection.

Exception

NA

Getting Enumeration to Iterate Collection of Integers Example

The following example shows the usage of Java Collection enumeration() method to get an enumeration on list of Integers. We've created a list of integers and navigated to each element using the enumeration object created using enumeration() method.

 
package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

public class CollectionsDemo {
   public static void main(String args[]) {

      // create array list object       
      List<Integer> arrlist = new ArrayList<>(Arrays.asList(1,2,3));

      // create Enumeration
      Enumeration<Integer> e = Collections.enumeration(arrlist);

      System.out.println("Print the enumeration");

      while(e.hasMoreElements()) {
         System.out.println("Value is: "+e.nextElement());
      }
   }    
}

Output

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

Print the enumeration
Value is: 1
Value is: 2
Value is: 3

Getting Enumeration to Iterate Collection of Strings Example

The following example shows the usage of Java Collection enumeration() method to get an enumeration on list of strings. We've created a list of strings and navigated to each element using the enumeration object created using enumeration() method.

 
package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

public class CollectionsDemo {
   public static void main(String args[]) {

      // create array list object       
      List<String> arrlist = new ArrayList<>(Arrays.asList("A","B","C"));

      // create Enumeration
      Enumeration<String> e = Collections.enumeration(arrlist);

      System.out.println("Print the enumeration");

      while(e.hasMoreElements()) {
         System.out.println("Value is: "+e.nextElement());
      }
   }    
}

Output

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

Print the enumeration
Value is: A
Value is: B
Value is: C

Getting Enumeration to Iterate Collection of Objects Example

The following example shows the usage of Java Collection enumeration() method to get an enumeration on list of Student objects. We've created a list of student objects and navigated to each element using the enumeration object created using enumeration() method.

 
package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

public class CollectionsDemo {
   public static void main(String args[]) {

      // create array list object       
      List<Student> arrlist = new ArrayList<>(Arrays.asList(new Student(1, "Julie"),
         new Student(2, "Robert"),new Student(3, "Adam")));

      // create Enumeration
      Enumeration<Student> e = Collections.enumeration(arrlist);

      System.out.println("Print the enumeration");

      while(e.hasMoreElements()) {
         System.out.println("Value is: "+e.nextElement());
      }
   }    
}
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 + " ]";
   }
}

Output

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

Print the enumeration
Value is: [ 1, Julie ]
Value is: [ 2, Robert ]
Value is: [ 3, Adam ]