Introduction to Programming

Here is what we are going to discuss

In the following subsections, we will discuss the most popular interfaces and classes of Java collections from standard libraries:

• The List interface and the ArrayList class – they preserve the order of the elements
• The Set interface and the HashSe class –  they do not allow duplicate elements
• The Map and HashMap interfaces – they store objects by with a key and thus allow key-to-value mapping

Please notice that most of the methods described in the following sections come from the java.util.Collection interface – the parent interface of almost all the collections, except those that implement the java.util.Map interface.