Black Friday is here! Take advantage of this unique opportunity and get up to 80% extra knowledge for free! Read more here
bf extended_2022

Lesson 8 - The Collections Java utility class - Getting and modifying

In the previous lesson, Queue and Stack in Java, we introduced the queue and the stack. In today's Java tutorial, we're going to focus on the Collections library class, which contains a large number of utility methods to simplify the work with collections.

The Collections Class

This class belongs to the java.util package. Its methods could be categorized into several categories:

  • getting data from collections
  • modifying existing collections
  • creating new collections

Getting Data From Collections

We can use the following methods to get useful information from a collection:

disjoint()

This method returns true, if two given collections do not contain the same elements:

final Collection<String> c1 = Arrays.asList("Carl", "Paul", "Michael");
final Collection<String> c2 = Arrays.asList("John", "Jack", "Peter");
final boolean disjoint = Collections.disjoint(c1, c2);
System.out.println("Collections don't contain the same elements: " + disjoint);

The result:

Console application
Collections don't contain the same elements: true

frequency()

Finds out


 

...End of the preview...
Continue further

You will gain knowledge worth hundreds of thousands for a few crowns

You've come here and that's great! We believe that the first lessons showed you something new and useful
Do you want to continue the course? Go to the premium section.

Limited offer: Learn all knowledge and save money

Buy lessons and exercise submitting one by one $7.20
Buy all currently available lessons with exercise submitting and other features for an exclusive price $1.44
Currently, you have $0
By buying this exclusive package, you'll have access to all 13 lessons in this course including exercise submitting while saving $5.76. This is a time limited offer for all lessons in this course. Buy it now and gain a limited 80% discount.
Buy only the lesson $0.90
Currently, you have $0

This article is licensed: Premium, by buying this article, you agree with the terms of use.

What will you get from us in the next lessons?
  • Unlimited and permanent access to individual lessons.
  • High quality IT knowledge.
  • Skills to help you get your dream and well-paid job.

Article description

Requested article covers this content:

In this Java tutorial, we'll look at the Collections utility class which contains useful methods for retrieving and modifying data in collections.

You gain credits by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

Article has been written for you by Petr Štechmüller
Avatar
Activities