From Array to ArrayList

Lesson X - 25 September 2019

How was the Preject?

Congratulations! OOP done

Three random questions...

• what is an abstract class?
• what is an interface?
• what is method overriding?

Data Structures

What are they?

A way to store and organize data so that it can be used efficiently

But I have Arrays!

Java Collections Framework

(doc)

ArrayList

(doc)

Why ArrayList is better than Array?

supports dynamic arrays that can grow as needed!

Package

a namespace that organizes a set of related classes and interfaces

Let's code!

Homework

• Write a program to find the second smallest element in an array of integers. Write a porgram to find the second smallest element in an array list of integers.
• Try to add new functionalities to the Country class, let's make sure that for every country we can track the bordered countries. Would a ArrayList be the best approach? If not, why not?

Credits

• Collections (simple): https://opensourceforu.com
• Collections (complex): https://medium.com/omarelgabrys-blog
• Photos: Unsplash