Java vs. JavaScript: A comparison of both languages

Java and JavaScript are two fundamentally different languages with different approaches. Java is a versatile language that needs to be compiled, whereas JavaScript is an interpreted scripting language.

Are there any similarities between Java and JavaScript?

If you’ve just started looking into scripting languages and web programming languages, or are considering learning how to code, you may have already come across Java and JavaScript. At first glance, these languages seem similar and considering their names, could maybe even belong together. While there are a few similarities between the two, the differences clearly outweigh them and upon closer inspection, it becomes obvious that they definitely do not belong together. At some point, you’ll probably ask yourself whether you need Java or JavaScript for your project. This article can help you answer this question.

Similarities and differences briefly explained

One thing Java and JavaScript have in common is the year that they were both released. Both came out in 1995. Java is an object-oriented programming language developed by James Gosling and Patrick Naughton for Sun Microsystems and has belonged to Oracle since 2009. Java needs to be compiled. To do this, it must go through the Java Virtual Machine (JVM), which interprets the code for the particular computer. The language is mainly used to create applications that can then be used on computers or in browsers. Java works platform-independently, which is why the code can be executed on practically all systems, as long as the Java Runtime Environment (JRE) is used.

JavaScript, on the other hand, is an object-oriented scripting language developed by Brendan Eich. It is also owned by Oracle, although, in contrast to Java, it has been with the company since 1997. It was originally called LiveScript but was renamed in 1996 to take advantage of Java’s popularity. Beyond that, Java and JavaScript have little in common. Initially, JavaScript was mainly used to create interactive content for web pages. Today, the language is also used on servers. JavaScript is an interpreted language, so it is read and translated during program execution. It is not part of the Java platform, but like Java it is partly based on C.

What distinguishes Java and JavaScript from one another?

It quickly becomes clear that Java and JavaScript are two completely different languages with their own approaches. In the following section, we’ll explain the differences in more detail.

Typing

Java is strongly typed and static, while JavaScript is weakly typed and dynamic. So with JavaScript, data types do not need to be explicitly named when declaring variables; instead, typing occurs during runtime. The situation is completely different with Java. Here, the data type is already checked beforehand and needs to be explicitly stated when a variable is being declared.

Operational purposes

Java takes a much broader approach and is suitable for desktop and server applications as well as different operating systems. JavaScript, on the other hand, has a different focus, which is much narrower. The language is largely used for applications within web browsers.

Operability

Java can run on its own. In order to do this, it needs the Java Virtual Machine (JVM), which ensures that a program also functions independently of other applications. JavaScript, on the other hand, is embedded in HTML and requires a browser, otherwise it can’t run.

Compiling

Before Java can be executed, the code first needs to be compiled, i.e., translated into binary code so that it can then be read by the Java Virtual Machine. Any errors in the syntax can be detected in advance. Then the code is executed in a package with a Java Archive or using a Web Archive from a virtual machine or a web container. JavaScript, the scripting language, chooses a different path and forgoes a compiler, preferring to use an interpreter instead. This executes the source code directly and does not translate it into machine language beforehand. This is typical of scripting languages.

Scope

Both languages are very extensive due to numerous frameworks and libraries like Spring or Hibernate for Java and jQuery or Node.js for JavaScript. The requirements of Java, however, are somewhat more extensive. In addition to the Java Virtual Machine, the Java Development Kit (JDK) must also be installed on the computer. Only then can you develop, test and run applications. JavaScript is much less demanding in this respect. You can create the code itself in a conventional text editor. If you want to run a program, all you need is a browser with a JavaScript plugin enabled.

Learning curve

If you are thinking about learning one of the two languages, you might be interested in knowing how difficult it is to learn each language. They are actually about the same, but it’s the requirements that could change things. Java is very easy to get acquainted with and has a very logical structure. Errors are detected early during the compiling process and therefore don’t cause major problems. However, if you want to scale applications or port them to another system, this requires patience and takes a bit longer. Getting acquainted with JavaScript is usually quite fast and things only get complicated when you want to try your hand at extensive projects.

Object orientation

Basically, both languages are object-oriented, whereas JavaScript can also be programmed in a functional or procedural way. In addition, the scripting language does not use classes. Objects are therefore not instantiated as classes, but existing objects are cloned. This approach is also known as prototype-based programming.

Syntax

The syntax of Java and JavaScript is quite similar in some areas. One reason for this is that the scripting language was partly inspired by its counterpart. However, while Java is primarily based on C, JavaScript is partly based on Python as well as other languages. When compared directly, it doesn’t take long to see the similarities and differences.

This is an example of code in Java:

// Example for Java
class Example {
    public static void main(String[] args) {
        System.out.println("Hello! This is what code in Java looks like.");
    }
}

For example, code in JavaScript is rendered in HTML like this:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>JavaScript example</title>
    <script>
        alert("Hello! This is what code in JavaScript looks like.");
    </script>
</head>
<body>
</body>
</html>

What are Java’s strengths and weaknesses?

Now that you know what makes Java and JavaScript different from each other, we’ll give you a brief overview of the individual strengths and weaknesses of the two languages. We’ll start with the slightly older language.

Java’s strengths

• Independence: Java is not dependent on any hardware and works without being tied to a specific platform. This makes the language very portable because it only needs the Java Virtual Machine to run. Multithreading and distributed computing are also possible with Java.
• Versatility: Java is a very good choice for numerous fields of application. Software, websites, servers and many other applications can be created with the language.
• Stability: Java is considered to be very stable. This is due on the one hand to the numerous functions and updates but can also be explained by the compiler and the fact that errors are detected in advance and can be fixed.
• Security: Java is also a very secure solution. The Java Virtual Machine prevents any unauthorised access.
• High-level language: Java is a high-level language, so it uses terms as a basis that are also understandable for humans. This makes it easier to get started and means that even beginners can understand the syntax relatively quickly.
• Object orientation: Java’s object-oriented approach allows programmers to reuse and customise code multiple times. This simplifies and improves workflow.

Java’s weaknesses

• Performance: Compared to languages that don’t need a compiler, Java is a little slower. It also doesn’t help that the automatic memory management reduces the speed.
• Price: Depending on the size of your project, the costs can be quite significant. The standard edition is fee-based when used for commercial work.
• Code: Although the code is easy to understand for humans, it is also much more extensive compared to some other languages. This can lead to long lines of code and may limit readability.

What are JavaScript’s strengths and weaknesses?

The second option in the Java vs. JavaScript duel also comes with its advantages and disadvantages. These are the most important to note:

JavaScript’s strengths

• Speed: The fact that JavaScript does not need to be compiled makes the language very fast. The fact that it runs in the browser and doesn’t need to take a detour via the server contributes to its fast speed. When comparing JavaScript to PHP and other scripting languages, it is definitely the fastest.
• Compatibility: Java is compatible with numerous other languages, programs and systems. It is therefore possible to integrate the language into a project and only use it for some parts. Integrating the language usually isn’t too difficult.
• Versatility: Java shows off its flexibility by interacting with other applications as well as in the different areas of an application. Whether websites, mobile development or now even on the server side, JavaScript often proves to be a worthwhile option.
• Scope: Through numerous libraries and frameworks, JavaScript is able to offer many functions and be optimised for individual requirements.

JavaScript’s weaknesses

• Security: The JavaScript code is also visible from the client side. This means it could become a gateway and therefore a security risk. Programmers must therefore be very careful about what information they make visible on the internet.
• Debugging: While the non-compiler approach has positive effects on speed, it can cause difficulties when debugging. Should problems occur, they are usually more serious and more difficult to fix.
• Interpretation: Different browsers can also interpret JavaScript differently. This can only be prevented by testing extensively with different browsers. On the one hand, this costs time and on the other, it is not always a safe solution.

What are Java and JavaScript’s fields of application?

As you can see, there are a lot of differences between Java and JavaScript. The two languages have very little in common, which is why you may end up wondering which language is recommended for which use case. JavaScript is a scripting language, which is best suited for website development. You can also count on the language for server-side applications. Java is more versatile and is suitable for operating systems, software, web applications, server solutions and system tools, among other things.