What Is Java, Anyway?

Java is one of the most widely used programming languages in the world, and there is a good chance you interact with something built in Java every single day.

It first appeared in the mid 1990s with a simple promise: write your code once, and run it almost anywhere, on any computer or device that has a Java Virtual Machine installed. That idea made Java hugely popular, and it never really stopped growing from there.

Where you will find Java in the real world

Two places stand out. The first is Android phones. Most Android apps are built using Java or a very close cousin language called Kotlin, so if you have ever tapped an app icon on an Android device, Java is probably somewhere behind the scenes.

The second is large web back-ends. Many big companies, banks, airlines, and online stores run their servers on Java because it is fast, reliable, and built to handle huge amounts of traffic without falling over.

• Android apps on millions of phones
• Server side systems that power large websites
• Banking and financial software
• Business tools used inside big companies

That combination, mobile apps on one side and heavy duty servers on the other, is part of why Java has stayed popular for so many years.

In this course we will build up slowly. You will start by printing a simple message to the screen, and by the end you will understand the basic building blocks that every Java program is made of.