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 unau­tho­rized 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 customize 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 optimized 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.