The Difference Between Java and Javascript

Learn the important differences between Java and JavaScript, and kickstart your career as a developer!

Java vs Javascript

Entering the world of web development, an aspiring developer can be overwhelmed by a multitude of programming languages to learn. Some coding languages have risen in popularity in recent years, namely Java and JavaScript. Anyone interested in learning to code has likely heard of both languages and may not be sure what the differences are and which one to learn first.

Java and JavaScript may sound like they’re two versions of the same thing, but in reality they’re not related or even very similar to each other. The main similarities between Java and JavaScript are the syntax and the fact that they can both be used in web applications on both the client side (front end) and the server side (back end). Let’s take a deeper look at what sets these two languages apart.

What Is Java?

Java, one of the world’s top coding languages, is used to build the back-end components of applications. Although users don’t see or interact with these components, they are essential for the front end to work. 

In more technical terms, Java is a class-based, object-oriented programming language. This is a type of programming where the structure and behavior of an object are defined by a class, which is a definition, or blueprint, of all objects of a specific type. In Java, programs are built and organized around collections of objects.

Java is what’s known as a compiled language, meaning that it has to be translated from source code written in the Java Development Kit (JDK) into bytecodes. These bytecodes are then executed in the Java Virtual Machine (JVM), which can be found in most any type of computer, operating system and platform. Java-based programs are platform-independent and can even be run in a browser. 

As Java code is being written, the JVM compiler checks the code thoroughly for possible errors. In addition, Java has rather strict rules for declaring variables and types. This makes Java reliable, which in tech terms is known as “robust,” as well as highly secure. Java can also support multi-threading, the capability to run multiple tasks simultaneously, maximizing CPU resources and optimizing performance. 

Because it’s so robust and versatile, Java is a strong choice for back-end web development. You can find Java in desktop applications, Android applications, and all types of web applications, including banking and financial, big data, social networks, and legacy software that’s been connected to web interfaces. 

Which companies use Java? 

If you peek behind the scenes at the back-end, you can find Java on Airbnb, Amazon Web Services, eBay, Uber, Netflix, Spotify, and Minecraft, just to name a few.

What Is Javascript?

Just like Java, JavaScript is widely known in the web development world. It’s risen in popularity to become the most popular coding language in use today. However, JavaScript is mainly used in front-end development to build dynamic and interactive web pages. It does this by manipulating different elements of the Document Object Model (DOM), the internal working structure of an HTML page. JavaScript is what makes something happen when, for example, you click a button on a web page. 

JavaScript is like its name says: a script. It’s not an actual programming language. Its technical definition is an “object-oriented scripting language.” JavaScript can also be called an interpreted language, as it’s interpreted by the browser in the moment without needing to be compiled like Java does. Though JavaScript is object-based, it’s mainly made up of functions. These functions are objects that have properties and methods. JavaScript is more dynamic than Java in terms of declaring variables and types. 

All JavaScript source code is written in a text editor and then executed on the client’s browser. However, although it was created as a client-side language, JavaScript can run on a server using Node.js, a runtime environment, making it equally effective as a back-end language.  

In addition to making web pages interactive, JavaScript is used for developing mobile apps, games, web apps, and building web servers. Its vast network of libraries and frameworks such as React, Angular, Node.js, jQuery and Lodash makes JavaScript a highly versatile choice for developers at all stages of their careers. 

If you're looking to learn JavaScript, try our free JavaScript mini-course and master the basics in a matter of hours!

Which companies use JavaScript? 

As you’ve seen above how Java and JavaScript serve different needs, it’s no surprise that the world’s most powerful companies tend to use both languages in their development. Microsoft, PayPal, Groupon, Netflix, Facebook and Google are just a few of the major tech giants that rely on JavaScript to run.

Java vs Javascript: Which Should You Learn First?

The answer here is: it depends! You really can’t go wrong with either language. And you don’t need to know Java to learn JavaScript, or vice versa. The best place to start is to think about your career and whether you’d rather work as a back-end developer on the server side or as a front-end developer. 

If you’re planning to work on desktop applications, Android apps, data analytics, or focus on the server side, it’s ideal to learn Java first. Java can teach you good coding habits from the beginning to help you build a strong foundation in object-oriented programming. Many large companies tend to look for developers with experience in Java, so learning it can boost your job prospects. 

On the other hand, if you’d rather build dynamic web-based applications or focus on the front end, JavaScript would be your best bet. JavaScript is easier than Java to learn for someone who’s just getting started. All you need is a text editor as well as a bit of base knowledge of HTML and CSS. Most front-end developers won’t need to know Java, but many back-end developers now need a clear understanding of JavaScript as major tech companies start shifting their back-end development toward Node.js.

Whether you choose to learn Java or JavaScript first, Ironhack can help you get there! Check out Ironhack’s Web Development Bootcamp, where you’ll get hands-on experience coding with cutting-edge languages and frameworks.

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