Java vs JavaScript: what are the differences?

Java and JavaScript are two fundamentally different languages ​​with divergent approaches. Java is a general-purpose language that must be compiled, while JavaScript is an interpreted scripting language.

Java and JavaScript: their name as (only) link¶

If you’ve just started using, thinking about, and learning about scripting languages ​​and web programming languages, you’ve probably already discovered Java and JavaScript. At first glance, these languages ​​act similar and, due to their names, appear to work together. This is however not true. There are certainly some common points between the two, but the differences are nevertheless clearly in the majority. Even interdependence is not appropriate. Instead, you’ll end up wondering whether you should use Java or JavaScript for your project. We help you find the answer to this question.

Commonalities and differences: summary¶

One of the common points between Java and JavaScript is the year of their respective first publication: these two languages ​​in fact appeared in 1995. Java is a object-oriented programming language developed by James Gosling and Patrick Naughton for Sun Microsystems. Since 2009 it has been part of Oracle. Java must be compiled and to do this executes the Java virtual machine (Java Virtual Machine or JVM) which interprets the code for the corresponding computer. The language is mainly used to create applications which can then be used on computers or in browsers. Java works independently of any platform, which is why the code can in principle be executed on all systems as long as the Java Runtime Environment (JRE) is used.

JavaScript, on the other hand, is a object-oriented scripting language developed by Brendan Eich and also owned by Oracle since 1997. It was initially called LiveScript, but was renamed in 1996 in order to take advantage of the popularity of Java. Furthermore, Java and JavaScript have little in common. Originally, JavaScript was primarily used to create interactive content for websites. Today, this language is also used on servers. JavaScript is a interpreted language, so it is read and translated during program execution. It is not part of the Java platform, but like Java, it is partially C-based.

Java vs JavaScript: detailed differences of the two languages¶

It quickly becomes clear that Java and JavaScript are two completely different languages, each with their own approaches. We discuss some of their differences in more detail below.

Standardization¶

Java is highly normalized and static while JavaScript presents a dynamic and lightweight normalization. In JavaScript, data types must not be named explicitly during variable declaration; normalization takes place during execution. In Java, things are quite different: the data type is checked beforehand and must therefore already be explicitly indicated during the declaration of variables.

Uses¶

Java adopts a significantly more comprehensive approach and is suitable for desktop and server applications, as well as different operating systems. JavaScript, on the other hand, takes another, much more limited angle: the language is mainly used for applications in web browsers.

Functioning¶

Java is capable of running autonomously. This presupposes the presence of the Java Virtual Machine (JVM) which ensures that a program also operates independently from other applications. JavaScript, on the other hand, is embedded in HTML and requires a browser to be an integral part of a web page. Language therefore does not work without this context.

Compilation¶

Before you can run Java, the code is first compiled, that is, it is translated into binary code so that it can be read by the Java virtual machine. This also allows syntax errors to be detected in advance. Then the code is executed in a package with Java Archive or Web Archive by a virtual machine or web container. The scripting language takes a different approach: JavaScript happens without compileand instead uses ainterpret. The latter directly executes the source text and does not first translate it into machine language. This approach is typical of scripting languages.

Scope¶

Both languages ​​are very complete thanks to many frameworks and libraries, like Spring or Hibernate for Java and jQuery or Node.js for JavaScript. However, the prerequisites for Java are more important: in addition to the Java virtual machine, you also need to install the Java Development Kit (JDK) on the computer; Only then can you develop applications, test them and run them. From this point of view, JavaScript is relatively undemanding. You can create the code in a traditional text editor. If you want to run a program, you only need a browser with an enabled JavaScript add-on.

Learning curve¶

If you are planning to learn one of the two programs, it is obviously interesting to know the corresponding difficulty level. Although it is similar for both, the requirements are different. Java offers a rather easy initiation and is designed very logically. Errors are detected early during compilation and therefore have no impact. On the other hand, if you want to evolve applications or transfer them to another system, you will need to be patient and allow some training time. In JavaScript, initiation is also very fast normally. Things only get complicated if you want to tackle many projects.

Object orientation¶

In principle, both languages ​​are object-oriented, but JavaScript can also be programmed functionally or procedurally. In addition, the scripting language does not use no class. Objects are therefore not instantiated like classes, but already existing objects are cloned. This approach is also called prototype-oriented programming.

Syntax¶

The syntax of Java and JavaScript is quite comparable in some areas. This can be explained, among other things, by the fact that the scripting language was partially inspired by its competitor. While Java is primarily C-based, JavaScript refers to Python and other languages. In a direct comparison, similarities and differences are quickly visible.

Here is an example of code in Java:

// Exemple pour Java
class Exemple {
   public static void main(String[] args) {
    System.out.println("Bonjour ! Voici à quoi ressemble le code en Java.");
  }
}

In JavaScript, the code for this example is presented in HTML:

<!DOCTYPE html>
<html lang="fr">
<head>
   <meta charset="UTF-8">
   <title>Exemple en JavaScript</title>
   <script>
      alert("Bonjour ! Voici à quoi ressemble le code en JavaScript.");
   </script>
</head>
<body>
</body>
</html>

Java vs JavaScript: what are the strong and weak points of Java?¶

Now you know what differentiates Java and JavaScript. So that you can better evaluate each of the strengths and weaknesses of the two languages, we present a brief overview. Let’s start with the oldest language.

Java Highlights¶

• Independence : Java does not depend on any hardware and works without connection to a specific platform. This language is therefore very portable, it only requires the Java virtual machine for its execution. Multithreading and distributed computing are also possible with Java.
• Versatility : Java is an excellent choice for many applications. Software, websites, servers and many other applications can be created with this language.
• Stability : Java is considered to be very stable. This is due to the many functions and updates, but is also explained by the compiler. Errors are indeed detected early and can be resolved.
• Security : Java is also a very safe solution. Unauthorized access is blocked by the Java virtual machine.
• Standard language : Java is a standard language and therefore uses terms that are also understandable by humans as a basis. This makes it easier to get started and allows beginners to understand the syntax relatively quickly.
• Object orientation : Thanks to Java’s object-oriented approach, programmers can use and adjust the code many times. This simplifies and improves the workflow.

Java Weaknesses¶

• Performance : Compared to languages ​​that do not use compiler, Java is a little slower. Automatic memory management also limits speed.
• Costs : Costs for Java can be considerable depending on the size of your project. The standard version is paid if used for commercial purposes.
• Coded : although the code is easily understandable by humans, it is much larger than that of some other languages. This can lengthen lines and decrease readability if necessary.

Java vs JavaScript: what are the strong and weak points of the scripting language?¶

The second option in this duel between Java and JavaScript also has advantages and disadvantages. The main ones are described below:

JavaScript Strengths¶

• Speed : JavaScript does not need to be compiled, so the language is much faster. Its concentration on the browser, without detouring on the server, also contributes to its speed. Even compared to PHP and other scripting languages, Javascript has the advantage of speed.
• Compatibility : Java is compatible with other languages, programs and systems. It is therefore possible and simple to integrate the language into a project and use it only for a specific domain. This integration generally works without problems.
• Versatility : Java is flexible not only in terms of interaction with other applications, but also in terms of diversity of areas of use. Websites, mobile development or now even on a server site: JavaScript is often a cost-effective option.
• Scope : Thanks to numerous frameworks and libraries, JavaScript can offer various functions and thus be optimized according to individual requirements.

JavaScript Weaknesses¶

• Security : JavaScript code is also accessible on the client side. It can thus become an access door and therefore present a security risk. Therefore, programmers must be very careful about what information they make visible on the Internet.
• Debugging : While the no-compile approach has a positive effect on speed, it can cause difficulties in terms of debugging. If problems do arise, they are, firstly, usually serious to resolve and secondly, more complex.
• Interpretation : Different browsers may interpret JavaScript differently. This problem can only be avoided by extensive testing measures on different browsers. This solution not only requires time, but is not always safe.

Java vs JavaScript: what is the scope of these languages?¶

As you can see, differences predominate between Java and JavaScript. Both languages ​​have little in common overall, which may lead you to wonder for which fields of application each of these languages ​​is recommended. JavaScript is a pure scripting language that is perfectly suitable for (continuous) website development. You can also rely on this language for server-side applications. Java is even more versatile and is suitable for operating systems, software, web applications, server solutions or system tools, among other things.