Java vs JavaScript: What’s the Difference?

Java and JavaScript might sound similar, but they have different roles in programming.

• Java is a powerful coding language that helps you build complex applications such as desktop software, mobile apps, and video games.
• JavaScript is a front-end programming language that adds interactivity to web pages.

This guide explores the key differences between Java and JavaScript in detail. You’ll learn about their features, use cases, applications, and their popularity in 2024.

What’s the Difference Between Java and JavaScript?

Java and JavaScript are two distinct programming languages that serve different purposes: 

✔️ You can use Java to create complex applications like mobile apps and enterprise software. It’s a statically typed language with strict rules, developed by Sun Microsystems (now Oracle) in the mid-1990s. Java uses an object-oriented approach and structures code with classes and objects.

✔️ JavaScript helps front-end developers build interactive web pages. It’s a dynamically typed, lightweight scripting language that runs directly in the browser. Netscape developed JavaScript in the mid-1990s and chose this name simply to capitalize on the popularity of Java at the time.

Let’s look at each of them in detail.

What is Java

Java is a general-purpose programming language—unlike other coding languages designed for specific tasks such as web development. In other words, it can help you build various software applications, from mobile games to complex programs.

Key features of Java

Here’s a closer look at some key aspects of Java:

• Java is an object-oriented programming language designed for creating well-structured and reusable code. In Java, programs are built around objects, which are small units containing data and instructions.

• One key feature of Java is static typing, where you define the data types (like numbers or text) that your variables will hold. This helps catch errors early in the development process.
• Java code is compiled into bytecode, a format understood by the Java Virtual Machine (JVM). The JVM acts as a translator, enabling the same bytecode to run on any system with a JVM installed. This makes Java programs platform-independent.

Here’s a sample piece of Java code that calculates the area of a rectangle:

This code defines a class named AreaCalculator with a main method. Inside the main method:

• We declare two variables, length, and width, to store the rectangle’s dimensions.
• We calculate the area by multiplying length and width.
• Finally, we use System.out.println to print the calculated area, and a message.

When to use Java

Java is popular for creating complex applications like enterprise software, Android apps, desktop apps, and even server-side web applications (though less common nowadays).

Java can aid both front-end and back-end development, but it’s primarily considered a back-end language. Here are its key use cases:

✔️ Android app development: Java remains the foundation for building most Android apps.

✔️ Enterprise software: It’s common to use Java for building complex applications in finance, healthcare, and other sectors. These applications often run behind the scenes, handling business logic. While other languages like Python are gaining traction here, Java still holds a strong position.

✔️ Big data & scientific computing: Java can handle complex calculations and has rich libraries, which make it a good choice for data analysis and scientific computing tasks.

✔️ Desktop applications: Java can also help you create standalone software programs with graphical user interfaces (GUIs) for desktops and laptops.

Java frameworks like Spring used to be popular for creating large-scale web applications. However, languages like Python and JavaScript (through Node.js) are more widely used for modern web development.

Pros and cons of Java

Pros	Cons
Handles complex tasks in enterprise software, big data, and mobile app development. It’s platform-independent and runs on various systems with the Java Virtual Machine (JVM). Built-in features and robust memory management reduce crashes and vulnerabilities. Helps you create structured and reusable code.	Java can be slower than some other programming languages due to the interpretation process. Java code can be more detailed than some languages. This complex language is not the best choice for basic scripting tasks. Java is mostly used for back-end development and has limited front-end web development applications.

What is JavaScript

JavaScript (JS) is a front-end programming language that makes websites interactive. It generates code behind features like:

1. Clickable buttons
2. Smart forms (forms that check if you’ve filled all the necessary fields before submitting them)
3. Interactive maps
4. Website animation
5. Live content updates (e.g., for websites that frequently update information like news headlines and shopping cart totals)

It’s common to use JavaScript alongside HTML and CSS when building web pages. Here’s a sample piece of JavaScript code that creates an alert message when a button is clicked:

Key features of JavaScript

You can use JavaScript to create various interactive website elements.

• JavaScript code is written in .js files and can be easily incorporated into web pages. It’s a lightweight scripting language that helps you add functionality without bogging down the website.
• Unlike Java, which requires a separate Java Virtual Machine, JavaScript code is interpreted directly by all major web browsers. So, users don’t need to download any special software to experience the interactive features powered by JavaScript.
• JavaScript is dynamically typed, meaning it figures out data types as the code runs. This makes it easier to learn for beginners.
• While not strictly object-oriented like Java, JavaScript uses simplified object-oriented concepts to organize code in a way that’s easier to understand and maintain.

When to use JavaScript

Here are the top use cases for JavaScript:

✔️ Creating interactive web pages: JavaScript helps you make web pages dynamic and interactive, enabling features like form validation, animations, and real-time updates.

✔️ Front-end web development: JavaScript works alongside HTML and CSS to enhance the look and feel of websites. It ensures a responsive user experience across different devices and web browsers.

✔️ Building web applications: JavaScript is often combined with frameworks like React, Angular, and Vue.js to develop complex web applications that run in the browser.

✔️ Mobile app development: JavaScript also helps you create native mobile apps through frameworks like React Native.

Pros and cons of JavaScript

Pros	Cons
JavaScript lets you create dynamic and engaging web experiences Runs directly in all major web browsers Enables flexible data handlingImproves code organization and maintainability Beginner-friendly and easy-to-learn	JS can sometimes be vulnerable to scripting attacks if not implemented securely. Complex JavaScript can slow down page load times. Limited to front-end development Can be trickier to debug compared to some other languages.

Are you looking to master JavaScript and other front-end languages? Learn at your own pace and build a strong coding portfolio with Mimo’s online front-end developer career track.

Java vs JavaScript: 7 Key Differences 

As you can see, Java and JavaScript are two entirely different programming languages. Let’s explore the Java vs. JavaScript topic in detail.

Feature	Java	JavaScript
Primary Use	Server-side development, enterprise software, Android apps	Front-end web development, interactive web pages
Execution	Compiled bytecode runs on JVM	Interpreted directly by web browsers
Typing System	Statically typed (data types declared upfront)	Dynamically typed (data types determined at runtime)
Object-Oriented	Yes (classes for creating objects)	Yes (prototypes for creating objects, looser approach)
Platform Independence	Yes (bytecode runs on any system with JVM)	Limited (primarily runs in web browsers)
Learning Curve	Steeper (stricter syntax, object-oriented concepts)	Easier (cleaner syntax, focus on web functionality)
Syntax	Verbose, formal, uses curly braces, semicolons	Clean, concise, uses less punctuation
File Extension	.java	.js

1. Primary use cases

Java: Works primarily on the server side (the mechanisms powering websites and applications). It’s the go-to choice for building the backbone of web applications, creating complex enterprise software, and powering Android apps.

JavaScript: JavaScript is used by front-end web developers. It helps you build interactive features and dynamic content for web pages.

2. Execution

Java: Takes a two-step approach. Your code is first compiled into bytecode, a universal format that can run on any system with a Java Virtual Machine (JVM) installed. This adds an extra layer of processing but offers better performance and security.

JavaScript: Skips this compilation step entirely. Instead, it’s interpreted directly by web browsers, making it quicker to set up and test your code.

3. Platform independence

Java: Once compiled into bytecode, Java code can run on almost any system with a JVM installed (Windows, Mac, Linux). This makes it a portable choice for developers.

JavaScript: JavaScript’s primary platform is web browsers (Chrome, Firefox, Safari, etc.). While frameworks like Node.js allow for some server-side use, it’s not its main strength.

4. Typing system

In programming, a typing system is a set of rules that define how data is categorized and used within a program. These rules specify what types of data (like numbers, text, or booleans) you can use and how they can be manipulated.

Java: Enforces static typing, meaning you have to declare data types (like numbers or text) upfront before using them in your code. This can make code more organized but requires stricter planning at the beginning.

JavaScript: Uses dynamic typing. It figures out data types on the fly as your code runs. This offers more flexibility for beginners but can be less predictable if you’re not careful.

5. Syntax

Syntax in programming is the rules that determine your code’s structure and organization. It defines how you write your instructions, including items like keywords, operators, etc.

Java: Java’s syntax is more verbose and formal. It relies heavily on curly braces, semicolons, and strict typing declarations to ensure code clarity and avoid errors.

JavaScript: has a cleaner and more concise style with less punctuation and higher readability.

6. Learning curve

Java: Generally has a steeper learning curve with its stricter syntax, object-oriented features, and emphasis on memory management create a steeper learning curve. It requires a solid understanding of computer science concepts.

JavaScript: It’s more beginner-friendly thanks to its focus on web functionality and a more concise syntax.

7. Building blocks

Java: Java is a full-fledged object-oriented language. It relies heavily on classes, which act as blueprints for creating objects. This structured approach makes code more reusable and easy to maintain for large projects.

JavaScript: JavaScript is often referred to as a scripting language. However, it incorporates object-oriented concepts to a certain extent through prototypes. Prototypes are objects that serve as templates for creating other objects. This approach offers more flexibility but can be less structured compared to class-based object-oriented languages like Java.

FAQs: Java vs JavaScript

Below, we answer some of the most common questions about Java and JavaScript.

Which is better: Java or JavaScript?

Deciding between Java and JavaScript isn’t about which is “better.” They’re distinct programming languages with unique strengths and applications. Java is a compiled language that operates on the server side, crafting complex desktop applications and Android apps. JavaScript, a lightweight and interpreted scripting language, operates in web browsers. It helps front-end developers create interactive web pages.

Should you learn JavaScript or Java?

The choice between learning JavaScript and Java for work and career depends on several factors, including your goals, interests, and the projects you want to work on.

You should learn Java if you’re interested in building applications such as desktop software or mobile apps. Many major corporations use this coding language in their back-end systems.

On the other hand, JavaScript is a good choice for those interested in front-end development. It’s also generally considered easier to learn for beginners thanks to its flexibility and syntax similarities to HTML and CSS. Java and JavaScript offer great career prospects and are in high demand in the job market. 

As of May 2024, there were 10,358 positions requiring Java and 8,068 positions mentioning JavaScript on Indeed.com within the US.

At the same time, JavaScript is a more popular and widespread language due to its web development applications. It’s the top programming language based on 2023 data, while Java ranks fifth.

This means that JavaScript’s community is more diverse and widespread, offering more support and learning materials. However, it’s best to rely on both community resources and a more guided learning experience to learn JavaScript.

For example, check out Mimo’s interactive front-end developer career track that covers all the necessary topics and helps you create a strong coding portfolio with real-life projects.

Which pays more: Java or JavaScript?

Both Java and JavaScript developers can earn competitive salaries in 2024. However, there are some factors that can influence your pay rate:

• Experience: As with most careers, developers with more experience in either Java or JavaScript will typically command higher salaries.
• Specialization: Developers who specialize in a particular area within their chosen language can potentially earn more. For example, it could be Java for enterprise software development or JavaScript for building complex front-end web applications with frameworks like React.
• Location: Geographic location can also affect your salary. Areas with a higher cost of living usually offer higher salaries for Java and JavaScript developers. 

However, since many coding jobs are remote these days, you don’t necessarily have to be restricted by geographical borders. According to Indeed.com data, the average annual salary of Java developers in the US was $91,721 as of May 2024.

This number reaches $111,721/year for JavaScript developers.

In reality, your remuneration will largely depend on the project scope and your particular skills.

Do you need to learn Java before JavaScript?

No, you don’t necessarily need to learn Java before JavaScript because these coding languages serve different purposes. JavaScript focuses on web development, while Java tackles server-side tasks.

Is Java easier than JavaScript?

Generally speaking, Java initially has a steeper learning curve, but it offers better organization in the long run. JavaScript might feel easier to start with, but it requires discipline and commitment too.

• Java’s formal syntax with stricter rules (think curly braces and semicolons) can feel more complicated for beginners. However, this structure enforces solid coding practices and becomes easier to manage in complex projects.
• JavaScript’s looser syntax might seem more straightforward at first. However, its dynamic nature can lead to unexpected behavior if you don’t handle it carefully.

Javs vs JavaScript: Key Takeaways

While Java and JavaScript share similar-sounding names, they’re distinct languages with unique use cases. Java focuses on complex server-side applications and Android development, while JavaScript helps you build interactive websites. Choosing between them depends on your career goals:

• Java offers a strong foundation for back-end development, especially in enterprise software.
• JavaScript is a crucial web development skill for building engaging user experiences. 

Are you ready to get started? Try Mimo’s front-end and full-stack development career paths to build a strong skillset and a competitive portfolio for a successful coding career.