Skip to content

Yet another programming solutions log

Sample bits from programming for the future generations.

Technologies Technologies
  • Algorithms and Data Structures
  • Java Tutorials
  • JUnit Tutorial
  • MongoDB Tutorial
  • Quartz Scheduler Tutorial
  • Spock Framework Tutorial
  • Spring Framework
  • Bash Tutorial
  • Clojure Tutorial
  • Design Patterns
  • Developer’s Tools
  • Productivity
  • About
Expand Search Form

Java Collection to Enumeration

farenda 2015-07-22 0

Problem:

When working with legacy code, you need to convert Java Collection to Enumeration. This example shows how to do that using Java Collections API features!

Solution:

The following Java code shows how to use java.util.Collections.enumeration(Collection) to convert Java List to Java Enumeration with elements of the same generic type:

package com.farenda.java;

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

public class CollectionsEnumeration {

    public static void main(String[] args) {
        List<String> coll = Arrays.asList("java", "util", "Collections");
        System.out.println("Collection: " + coll);

        // convert a Collection to Enumeration of the same type:
        Enumeration<String> en = Collections.enumeration(coll);
        System.out.println("Enumeration (no toString): " + en);
        while (en.hasMoreElements()) {
            System.out.println(en.nextElement());
        }
    }
}

Simple, no? :-) The only thing you have to keep in mind is that the internal implementation of Enumeration interface doesn’t provide it’s toString() method, so it won’t show its elements, what can be seen when running the example:

Collection: [[java, util, Collections]]
Enumeration (no toString): java.util.Collections$3@677327b6
java
util
Collections

As you can see, we had to iterate over the enumeration and print items one by one. Also, Java Enumeration doesn’t implement java.lang.Iterable, so it can’t be used with for-each loop.

Share with the World!
Categories Java Tags java-collections
Previous: Java empty List/Collection and null check
Next: Java List sublist

Recent Posts

  • Java 8 Date Time concepts
  • Maven dependency to local JAR
  • Caesar cipher in Java
  • Java casting trick
  • Java 8 flatMap practical example
  • Linked List – remove element
  • Linked List – insert element at position
  • Linked List add element at the end
  • Create Java Streams
  • Floyd Cycle detection in Java

Pages

  • About Farenda
  • Algorithms and Data Structures
  • Bash Tutorial
  • Bean Validation Tutorial
  • Clojure Tutorial
  • Design Patterns
  • Java 8 Streams and Lambda Expressions Tutorial
  • Java Basics Tutorial
  • Java Collections Tutorial
  • Java Concurrency Tutorial
  • Java IO Tutorial
  • Java Tutorials
  • Java Util Tutorial
  • Java XML Tutorial
  • JUnit Tutorial
  • MongoDB Tutorial
  • Quartz Scheduler Tutorial
  • Software Developer’s Tools
  • Spock Framework Tutorial
  • Spring Framework

Tags

algorithms bash bean-validation books clojure design-patterns embedmongo exercises git gof gradle groovy hateoas hsqldb i18n java java-basics java-collections java-concurrency java-io java-lang java-time java-util java-xml java8 java8-files junit linux lists log4j logging maven mongodb performance quartz refactoring regex rest slf4j solid spring spring-boot spring-core sql unit-tests

Yet another programming solutions log © 2021

sponsored