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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:

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.
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:

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.
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