Java vs. JavaScript: What’s the Difference?

9 min read

Searching for opportunities to build your skill set as a freelancer? Learning a new programming language is a great way to improve your resume! Many companies seek to hire or contract coding experts for software development gigs. 

Two popular programming languages are Java and JavaScript. You may assume that they are related because of their similar names — but they’re very different. 

Knowing the major differences between Java and JavaScript can help you decide which to learn for your career in web development.

What is the difference between Java and JavaScript? Java is an object-oriented programming language used in back-end development to create programs that can run on nearly any platform. JavaScript is an object-based scripting language primarily used in front-end development to make web pages more interactive for users.

In other words, Java converts entire programs into machine language and JavaScript converts scripted instructions within a program into machine language. 

What is Java?

Java is a methodical high-level programming language that allows you to build applications from the ground up. It’s a statically typed language, meaning it’s very rigid and must be compiled. 

Java was first released in 1996 by Sun Microsystems. James Gosling created it as a general-purpose IT language that could be used to run server-side automation. The company launched it with the slogan, “Write once, run anywhere.” The Oracle Corporation acquired Sun Microsystems in 2010.

Since then, Java has become a valuable tool for creating applications and performing big data computing.

Here is an example of Java text in an Integrated Development Environment:

Java

What’s it used for?

Because of its strict syntax and endless possibilities, Java is more suited to mobile app development, especially for Android devices. Java developers often work on lengthy projects in big, established industries that need dedicated apps for their users.

The language is useful for server-side programming, automated virtual operations, big data processing, and even programming hardware like smart devices. It’s the top language for virtual reality, continuous integration, DevOps, artificial intelligence, and application programming interfaces (API).

Well-known companies that use Java applications include Netflix, Spotify, Uber, Pinterest, Airbnb, and Amazon. Web application servers like Apache Tomcat and IBM WebSphere are based on Java.

Key Features

Key features of Java:

  • Object-oriented programming (OOP)

  • Capable of multithreading

  • Compiled language

  • Requires class declarations

  • Supports dynamic loading and compilation

  • Platform-independent

  • Used for server-side apps and back-end development

  • More simple and independent than C or C++

  • Secure and robust

  • Ideal for mobile applications, big data, and large-scale projects

Java developers must work within inflexible syntax constraints that require class declarations of all variables. As a class-based language, Java demands that data types must remain consistent within its code. The Java Virtual Machine (JVM) then converts the Source code into machine-readable data as bytecode.

Java has many precise requirements — even for the simplest functions — because you’re programming operations from the ground up. Every element needs to be meticulously approached.

The upside is that this gives you wider-ranging opportunities when creating an application. You can make something for standalone operation with cross-platform functionality because it has fewer dependencies. Plus, Java offers concurrency — capacity to work with multiple threads.

What is JavaScript?

JavaScript provides front-end interactivity on web applications. It’s a dynamic, client-side scripting language that is limited to operating within existing confines such as HTML. JavaScript is like CSS but offers on-page interactivity.

Netscape developed JavaScript in 1995 for use in web development as a tool alongside HTML and CSS. The language was first called Mocha and then LiveScript before receiving its current name. For years, it was the only major programming language that can be used in most web browsers. (WebAssembly has been gaining traction for the last 10 years as an alternative.)

Here is an example of JavaScript text within HTML:

Javascript

What’s it used for?

JavaScript code is simple and flexible. It has less rigid syntax, so you can reassign variables to values with fewer specifications of data types like class or function. That makes JavaScript code ideal for use in web development. 

You can jump in and begin churning out JavaScript code quickly, but you have to do so within the bounds of an existing HTML framework. 

The language is useful for client-side scripting, creating web- and browser-based games, web-based VR, and social media. Well-known companies that rely on JavaScript for front-end development include Microsoft, Walmart, PayPal, Facebook/Meta, Ebay, and LinkedIn.

Key Features

Key features of JavaScript:

  • Object-based scripting language

  • Dynamic typing

  • Client-side scripting

  • Functional style

  • Interpreted language

  • Validates user inputs

  • Simple calculations

  • Not easy to debug

  • Front-end development (and back-end development via Node.js)

  • Ideal for use in web browsers

Netscape designed JavaScript for manipulating front-end website functions to give users opportunities to interact with the page. The simple code allows you to click, drag, scroll, type, select, and modify in real time without needing to reload the page.

Ongoing, open-sourced development has expanded JavaScript well beyond its initial design. Thanks to Node.js, JavaScript’s value and functionality for developers have exploded. This framework opened the door to back-end web development. 

It now has the capability to follow a class-based structure, though it’s not a requirement like it is for Java. Node.js makes it easy to build a full-stack application within the JavaScript runtime environment.

Similarities

Java and JavaScript are largely dissimilar, but they have some things in common. They’re both:

  • OOPs: capable of processes like encapsulation, inheritance, and polymorphism

  • Essential for digital development: usable for front-end development (with a Java applet) and back-end development

  • Platform-independent: Cross-platform compatible and can run on servers or browsers

  • Easy to learn: Relatively simple to comprehend compared to other programming languages like Python

  • Advantageous tools: both programming languages offer immense value for aspiring developers

Differences

Here is a short, simple list of the key differences between Java and JavaScript:

  • Typing: Java’s is strong; JavaScript’s is loose

  • Language: Java is static (values are established at compile time); JavaScript is dynamic (values can be changed at runtime)

  • Scope: Java’s is block-level; JavaScript’s is function-level

  • Compilation: Java code is compiled in bytecode first; JavaScript language is all text

  • Concurrency: Java is thread-based and can run multiple; JavaScript is event-based and can only run singly

  • Primary use: Java specializes in back-end (servers); JavaScript specializes in front-end (user scripts)

  • Objects: Java views them by classes; JavaScript is prototype-based

  • Debugging: Java performs pre-run debugging during compilation; JavaScript only debugs when running

  • Platforms: Java runs standalone thanks to JVM; JavaScript is run on a browser

  • File extensions: Java and JavaScript use different file extensions (.java vs. .js)

  • Visibility: Java has hidden source code; JavaScript has publicly visible code

  • Security: Java is robust and resists manipulation; JavaScript is susceptible to third-party access

  • Maintenance: Java programs require less long-term upkeep; JavaScript is difficult to maintain

Those are the primary ways JavaScript is different from Java. Both programming languages have their advantages when you’re creating or enhancing an application.

Advantages of Java

  • Object-oriented, so it’s easier to implement

  • Easier to learn than C or C++

  • Better at debugging than JavaScript

  • Offers more security and error mitigation 

  • Supports multiple inheritances and multithreading

  • Can run independently on nearly any platform

  • Better for creating apps for mobile operating systems

  • Easy to reuse code

  • Has automatic garbage collection

  • Requires less long-term maintenance

Advantages of JavaScript

  • Involves a smaller set of commands

  • Easy to make in-line definitions

  • Better for client-side validation and input

  • Requires less memory than Java

  • Functions well with GUI features

  • Doesn’t require anything special to run code — whereas Java requires a JDK

How to Choose What to Learn: Java or JavaScript

Now that you understand the differences between Java and JavaScript, let’s take a look at how these programming tools can help your career. Aspiring developers commonly ask these questions when determining their next professional move.

Is Java or JavaScript used more?

JavaScript has been the more widely used programming language for many years. Millions of developers around the world use JavaScript. Its popularity has soared in the past decade with the prevalence of open-source software and cloud technologies. 

Java programming is still valuable in computing, but its popularity has been declining recently. Its usefulness in programming has become more select, whereas JavaScript is becoming broader — especially with the launch of Node.js.

Should beginners learn Java or JavaScript?

That depends on why you’re learning a programming language and what type of work you want to do. Java programming takes longer and involves bigger projects, while JavaScript is fast and direct. Which sounds more appealing to you? 

Start by watching some tutorials on Java and JavaScript. There are tons of videos created and explained by programmers that can give you an idea of which language fits your interests.

Which is easier to learn: Java or JavaScript?

Many developers say that Java provides a more accessible entry point into programming. Its strict syntax provides a thorough foundation for learning the basics of programming. Yes, Java is more rigorous than JavaScript, but dynamic typing can be confusing for beginners. A statically typed language provides a predictable framework for foundational syntax education.

Familiarity with JavaScript is not required for learning Java, nor should Java be used to learn JavaScript. They’re distinctly separate languages that are used for very different development projects.

Does Java or JavaScript offer better job potential?

Both languages have their benefits, but which offers more potential in the job market? 

Currently, JavaScript is more in demand as more companies need front-end programmers for quick, brief work. But, many more people know JavaScript, so you’ll compete against more JavaScript developers in the industry vying for those gigs.

Java jobs are less common. But, they take longer to complete and thus tend to pay better. Plus, fewer programmers are Java experts. A good career choice could be to master both Java and JavaScript, as knowing both will maximize your value to employers.

Want more help kicking your freelancing career into high gear? Join the MVP Match freelance network, where you can find the latest contract opportunities in the IT industry. We’ve connected many talented workers with the companies in need of their expertise — and we can do the same for you!

About the Author

Match wants to bridge the perspectives of talents and companies, and Marta’s job is to blend all the elements without burning the engine. She translates backstage know-how into practical insights and stories. What can’t be written on a blog will land on socials as a meme. She believes that shaping the #futureofwork is all about transparency and courage in communication. While collaborating with writers and authors from all over the world, she makes sure that everything that ends up on the Match blog makes the bridge stronger than ever.