Java vs. JavaScript: What Are They and Why Are They So Different?

If you’re new to programming, you’ve probably heard of Java and JavaScript. And naturally, you might assume they’re basically two versions of the same programming language.

They’re not.

Despite having similar names, Java and JavaScript are separate programming languages that were created for different purposes. So why do they have almost the same name?

Let’s break it down.

What Is Java?

Java is a programming language that was developed at Sun Microsystems and released in the 1990s.

One of the big ideas behind Java was “write once, run anywhere.” Instead of writing completely different programs for different types of computers, Java programs can run through something called the Java Virtual Machine, or JVM.

Think of the JVM as a middle layer between your Java program and the computer running it.

Java has been used for things like:

• Business and enterprise software

• Backend systems

• Android development

• Desktop applications

• Large software systems

• Games and other applications

One famous example is Minecraft: Java Edition, which—as the name suggests—was built using Java.

Java is also a statically typed language. This means programmers generally declare what type of information a variable is supposed to contain.

For example:

int age = 25;

Here, int tells Java that age is supposed to contain an integer.

So What Is JavaScript?

JavaScript is another programming language that appeared in the 1990s, but it was created for a very different reason.

It was originally developed to make websites interactive.

Remember our previous discussions about HTML and CSS?

A simple way to think about the three is:

HTML = structure

CSS = appearance

JavaScript = behavior

Imagine a website with a button.

HTML can create the button.

CSS can make the button blue, change its size, and give it rounded corners.

JavaScript can decide what happens when you click it.

That could mean opening a menu, submitting a form, changing something on the screen, loading more information, or performing a calculation.

Today, JavaScript has grown far beyond simple website buttons. It can also be used on servers, in applications, and in many other types of software.

Are Java and JavaScript Related?

Not in the way their names make it sound.

They have some similarities because they're both programming languages and share certain programming concepts, but JavaScript is not a smaller or web-based version of Java.

Learning Java does not mean you automatically know JavaScript, and learning JavaScript does not mean you automatically know Java.

It’s a little like car and carpet.

The words look related.

The things themselves? Not so much.

Then Why Is It Called JavaScript?

This is where things get interesting.

JavaScript was originally created at Netscape in 1995 by Brendan Eich. Early versions of the language went through names including Mocha and LiveScript.

Around the same time, Java was receiving a huge amount of attention in the technology industry.

Netscape and Sun Microsystems announced JavaScript under its new name in December 1995.

So the similarity between the names has a lot more to do with the technology landscape and marketing of the 1990s than JavaScript actually being a version of Java.

And nearly three decades later, that naming decision is still confusing new programmers.

Java vs. JavaScript

Here’s the simplest way to remember the difference:

Java is a general-purpose programming language commonly associated with applications, backend systems, enterprise software, and other larger software projects.

JavaScript became the programming language of interactive web pages and is now used throughout modern web development and beyond.

They have different rules, different ecosystems, and different common uses.

Most importantly:

JavaScript is not Java.

Which One Should You Learn?

That depends on what you want to build.

If you're interested in web development, JavaScript is extremely useful because it works alongside HTML and CSS to create interactive websites.

If you're interested in areas such as backend development, enterprise software, or certain application-development paths, Java may make more sense.

But you don't have to choose one forever.

Programming languages are tools. As you learn more about programming, you'll start realizing that understanding the underlying concepts can make learning additional languages much easier.

The Takeaway

Java and JavaScript might have confusingly similar names, but they're two different programming languages.

JavaScript wasn't created as the “script version” of Java, and Java isn't simply a more advanced version of JavaScript.

So next time you hear someone mention JavaScript, remember:

Java ≠ JavaScript.

And now you know why.