What are Java Collections and how do I use them?

What are Java Collections and how do I use them?

Java Collections are a framework that provides classes and interfaces for storing and manipulating groups of objects. They include lists, sets, and maps.

Can you explain the difference between a List and a Set?

Sure! A List allows duplicate elements and maintains the order of insertion, while a Set does not allow duplicates and does not guarantee any specific order.

How do I iterate over a List in Java?

You can iterate over a List using a for loop, an enhanced for loop, or an iterator. For example, using an enhanced for loop: for (String item : list) { System.out.println(item); }.

What is the best way to store unique items?

The best way to store unique items is to use a Set, such as HashSet or TreeSet, depending on whether you need fast access or sorted order.