Difference between Java and JavaScript
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Java and JavaScript are two popular languages used across many domains in software engineering. Despite having similar names, there is a considerable difference between Java and javascript in syntax, features, and applications. This, in turn, helps us understand when it's favorable to use one over the other. For enterprise applications and scalable web services, Java is a great choice. On the other hand, JavaScript is best suited for building client-side web applications.
Scope of Article
- The article gives a high-level introduction to Java and JavaScript.
- The article compares Java vs JavaScript and finds out some similarities and difference between Java and JavaScript.
- The article defines the features, advantages, disadvantages, and applications of each language.
- The article does not claim that one language is better or worse than the other. It simply helps you understand where each would be suited best to a particular use case.
Introduction to Java and JavaScript
Highlights:
JavaScript was named after Java for merely marketing reasons and not because it was considered a subset of Java.
Java came out in 1995 to power small electronic devices like setup boxes. It got so popular that inventors of JavaScript used its name to gain traction among companies and engineers.
Today, both Java and JavaScript are extremely popular due to their own advantages, and in the domain of software engineering dominate.
However, it's interesting to draw a comparison of Java vs JavaScript.
- Java is considered a high-level programming language capable of powering different applications.
- JavaScript, on the other hand, is considered a scripting language. A scripting language does not need a compiler and is directly interpreted at runtime. With JavaScript, the web browser is the interpreter that directly executes JavaScript at runtime.
Features of Java
Every language provides some features out of the box that makes it stand apart from other similar programming languages. The most common features of Java include:
- It runs on a virtual machine called Java Virtual Machine, an environment used to provide some virtual configuration to a physical device.
- It follows the object-oriented programming methodology.
- It is platform-independent, meaning it can run on any platform like the web, android, etc.
- It's strongly typed in nature, meaning that you need to define the type of a variable at the time of declaration.
- It performs static type checking, implying that all your variable types are validated and evaluated at compile time.
- It is multithreaded by default, or in other words, it can perform multiple tasks at the same time.
Features of JavaScript
Similarly, some common and popular features of JavaScript include:
- It is a scripting language that runs directly on a browser.
- It supports both functional as well as object-oriented programming methodology*. This means that you can write your code using functions or classes and objects.
- It is lightweight since it doesn't need a compiler.
- It is weakly typed and performs dynamic type checking. So you can create variables without worrying about their types and also assign values about different types to these variables at runtime.
- It supports both frontend and backend technologies on the client and server. This means that you can use it to create a user interface on the web or interact with a database.
Advantages & Disadvantages of Using Java
Highlights:
- Java's platform-independent, strongly typed, and multithreaded nature, memory management techniques, and security are its key advantages.
- Long, verbose(lengthy), and complex code, along with no support for functional programming, is its key disadvantage.
Let's look at some of the main advantages of Java that make it stand out against other programming languages.
Advantages
- We know that Java is compiled to bytecode using its own compiler called JVM or Java Virtual Machine. Therefore, any platform or operating system that has JVM configured and installed can run your Java code. This gives Java the versatile nature it has to develop applications. You can use Java to write platform-independent code, i.e., code that can be run on any platform like desktop, mobile, embedded system devices, etc.
- Often, when creating applications at scale, you require concurrency that enables your code to perform multiple tasks simultaneously. By nature Java is multithreaded, meaning you can perform multiple tasks in your application at the same time.
- Finally, being a strongly typed language, Java advocates developers to write type-safe code. Moreover, it performs type checking at compile time, so even if you make some type of errors, Java will let you know about them beforehand. Hence you can understand these types of errors and fix them well within time without letting your application break when it's running.
Disadvantages
- With Java, you're only allowed to write code following object-oriented programming methodology. However, this can impose a learning curve for beginners who may not be well-versed in that kind of programming pattern.
- Moreover, Java's syntax is a little more complex and lengthy than other languages. This, in turn, leads to lengthier and makes it more prone to errors and bugs.
Advantages & Disadvantages of Using JavaScript
Highlights:
- JavaScript's easy syntax, extensive ecosystem, powerful frameworks, and support for functional programming makes it an ideal scripting language for the web.
- It's weakly typed nature and dynamic type checking are its biggest disadvantages.
Advantages
- Unlike Java, JavaScript code is simple to write and easy to understand. Also, it has a more precise syntax than other languages. For instance, semicolons aren't mandatory to indicate the end of a statement in JavaScript.
- Moreover, it offers support for functional programming alongside object-oriented programming. This, in turn, makes it easy to get started for developers who're new to programming. Overall, the learning curve for JavaScript is quite narrow compared to Java earlier.
- At present, JavaScript dominates the client side of web applications. This is because of the extensive tooling, frameworks, and libraries that the JavaScript open-source ecosystem provides.
Disadvantages
- A major drawback with JavaScript is its weakly typed nature and dynamic type checking. Type errors can lead to the crashing of your program or application. JavaScript's weakly typed nature leads to bugs and errors in the program that are hard to debug.
- Moreover, JavaScript only detects these errors at runtime so there is no way of knowing beforehand if you've made a mistake in your program.
- Luckily, this problem can be combatted by using TypeScript, a strongly-typed version of JavaScript developed by Microsoft.
Applications of Java
- Java's versatile nature makes it fit for almost any kind of application that you wish to develop. However, that doesn't mean it's the best choice to create any kind of application.
- Java's advantages make it a great choice for creating desktop, native android, and embedded systems applications. Another good and widely used application of Java includes making backend services.
Applications of JavaScript
- Since JavaScript is the sole language used inside browsers, it's the preferred choice for making client-side web applications.
- There is a multitude of frameworks and libraries like ReactJS, Angular, VueJS, Svelte etc that allow you to create rich and high performant single-page applications on the web.
- However, you can even use it to create cross-platform mobile applications using a popular JavaScript framework called React Native. Using its popular server-side framework called NodeJS, you can also use it to create backend web services.
Companies Using Java
Java is a popular choice for creating scalable web services and is therefore used by companies such as Airbnb, Uber, Instagram, Google etc, for some of their microservices.
Companies Using JavaScript
Almost every company on the internet uses JavaScript for the front end of their web applications. Netflix, Airbnb, and Spotify all use JavaScript to create rich and interactive user interfaces for their web applications.
Paypal, Medium, and Uber also use JavaScript's server-side framework NodeJS for some of their backend microservices.
Similarities between Java and JavaScript
Highlights:
Both Java and JavaScript support object-oriented programming and server-side development.
Let's look at how Java and JavaScript are similar in some of their features.
Support for Object-Oriented Programming
Object-Oriented Programming is a programming construct that allows developers to build systems around objects with the help of encapsulated entities called classes`. Thus most of the logic of an application is tied to these classes and their data members.
This is in contrast to functional programming, where developers use and invoke functions to drive the logic of their application. Object-Oriented Programming is an old, trusted, and robust methodology for creating large and scalable applications.
Both Java and JavaScript allow you to encapsulate your logic in the form of classes and use their instances called objects to manipulate data. The great thing about this similarity is that you can easily write object-oriented code in both languages if you're well-versed in object-oriented programming.
Server-Side Development
Almost every web application has a server component that interacts with a database. Server-side development refers to creating web services that can be consumed via your web application. It's like the backbone of any web application. For instance, your favorite websites, before authenticating, you check the validity of your credentials through a web service. This service is server-side code.
Both Java and JavaScript support their backend technologies for server-side development. Java provides frameworks like Spring, JBoss and Apache to write server-side code, create web services, etc.
Similarly, JavaScript has its server-side framework called NodeJS that can be used to create web services. These web services can then be used across mobile applications, web applications, desktop applications, etc.
Therefore, if you wish to build backend services, either will come in handy with a database.
What is the Difference between Java and JavaScript?
- Java is considered a high-level programming language capable of powering different applications.
- JavaScript, on the other hand, is considered a scripting language. A scripting language does not need a compiler and is directly interpreted at runtime.
Where the similarities help us understand how Java and JavaScript can be correlated to each other, the difference between Java and JavaScript gives an insight into how each of them competes against the other in various use cases.
| Java | JavaScript |
|---|---|
| Java is a compiled language. | JavaScript is an interpreted language. |
| Java code is compiled to bytecode which runs on Java's compiler called Java Virtual Machine(JVM) | JavaScript is directly interpreted in a web browser and doesn't need a compiler |
| Java is multithreaded by default and uses it to support concurrency in a program. In other words, by nature, it supports the execution of multiple tasks simultaneously. | JavaScript is single-threaded and uses external APIs like callback queues and event loops to add concurrency to a program. So unlike Java which can run multiple tasks simultaneously, JavaScript alone cannot perform multiple tasks at the same time. It needs the help of external tooling that web browsers assist in. |
| Java only permits object-oriented programming. | JavaScript allows both functional as well as object-oriented programming. |
| Java is strongly typed and performs type checking at compile time. | JavaScript is weakly typed and determines types of variables at runtime. |
Java vs JavaScript: When to Use Which Language?
If you're looking to create a desktop or an embedded system application, Java should be your go-to language since it provides better support for developing this kind of application than JavaScript.
If you're developing the user-facing side of a web application, undoubtedly JavaScript is the best and probably the only choice you have.
While the above segments are clear, it's often debatable and opinionated as to which language should be the preferred choice when it comes to server-side development. Java has been used for a long time for developing web services in contrast to JavaScript. So Java is definitely the safer option. However, if you already know JavaScript and are already using it on the client side of your web application, you might as well use it on the server side as well. So for server-side development, your preferred choice should depend on the exact use case and how well you're versed in these languages.
Similarly, native mobile apps also need to deeply evaluate your use case. If you're focusing on performance and want to build a complex and scalable mobile app, Java should be your preferred choice. If your priority is developing a cross-platform app using a single codebase, go for JavaScript.
Conclusion
- Java is a strongly typed, compiled, and multithreaded language that is fit for creating scalable backend services.
- JavaScript is a weakly typed and interpreted scripting language used extensively for creating web applications.
- Java is the optimal choice for creating embedded systems high performant android and desktop applications.
- Depending on the use case, JavaScript can be a great choice for creating web services or cross-platform mobile applications.