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Главная страница » The age-old question: what is the difference between Java and JavaScript? Detailed guide

The age-old question: what is the difference between Java and JavaScript? Detailed guide

    For some, the answer to the question about the difference between Java and JavaScript is obvious – this is where jokes about the similarities between a carpet and a car begin (Java is similar to JavaScript in the same way that “car” is to “carpet”). Despite this, some people may still have the misconception that these are two names for the same language or that the technologies are closely related. clarifies the situation a little.

    What is Java?

    Java is a general-purpose object-oriented programming language created in 1995 by Sun Microsystems. It was developed on the basis of C and C++, depriving such low-level characteristics as pointers and open memory management, which greatly simplified the work of developers.

    What is JavaScript?

    JavaScript is the most commonly used language for designing dynamic web pages. It was released in 1995 by Netscape Communications, first under the name Mocha, then LiveScript. The modern version of the name the language received as a result of the popularity of Java – the creators decided to take advantage of the situation and make the name of the new language more recognizable, and along the way they caused a misunderstanding that continues to this day.


    Java is a fairly universal language. It is most popular for mobile and desktop development, but it is also widely used for backend, data processing, and game creation.

    If you’re interested in web development, JavaScript is worth considering. It was primarily intended for this direction, in particular the front end, although now it is also popular in the backend. Other areas of use: game development, mobile applications.

    It should be noted that languages ​​are not limited to these areas, but in other industries they can be found much less frequently.


    A kind of slogan that reflects the goal of creating Java – “Write once, run anywhere.” It’s a platform-independent language, and it’s not just about operating systems – it also applies to different devices. The main thing is that they must have Java Virtual Machine (JVM) installed – a special environment in which the code runs.

    JavaScript doesn’t require any virtual machines to run—the code runs directly in the browser. The exception is the Node.js framework – it is used for programming the server part.

    Development environment

    The situation is similar with the process of creating programs. Java requires pre-installation of additional components. First, the Java Development Kit. It includes development tools as well as another element – the Java Runtime Environment (JRE). In turn, this part is responsible for the libraries and files needed to run the code. The JRE also includes the previously mentioned JVM. To get started with Java, you need to download and configure all of the above.

    With JavaScript everything is much simpler. To create your own dynamic websites, you don’t need to install anything—all you need is a code editor and a browser.


    JavaScript was developed based on C syntax, just like Java, but they have little in common.

    One of the differences is that Java is a compiled language. This means that the application must be completely translated into a machine-readable version before launching, a process that must be carried out after every change in the code. C, C++, C# work according to the same scheme.

    JavaScript is a scripting language. The program is interpreted into computer-understandable commands at run time. On the one hand, this approach is slower, since the interpreter must re-evaluate the string every time it encounters it. But the advantage is the ability to modify the code on the fly – there is no need to compile everything when a small part has been changed. Other examples of scripting languages ​​are Python, PHP.

    In fact, being scripted/compiled is not a characteristic feature of the language itself. If you wish, you can change the approach to working with them; there are simply traditional solutions that are used more often. If you look deeper, Java generally combines both principles. But usually it is called compiled.

    Java is a language with strict static typing – that is, the types of all data are checked at the compilation stage. If the developer makes a mistake, the code simply won’t run. JavaScript is a non-strict dynamic language – types are defined after the start of work, and the programmer does not even have to specify them himself.

    Both languages ​​follow the object-oriented programming (OOP) paradigm. However, JavaScript is somewhat different from other languages ​​in this regard. It is sometimes called object-based. Java supports classes – unique templates, on the basis of which new entities are already created. In JavaScript, developers work directly with objects, without classes. The implementation of the main principles of OOP is also somewhat different.

    For example, inheritance. In Java it is based on classes. The developer can create a new class, a template that extends the capabilities of the parent one. And then get instances of it that have common behavior. Therefore, the object is conditionally the final product; after its creation, the internal structure cannot be expanded. Here the concepts of objects and classes are clearly distinguished.

    Inheritance in JavaScript is called prototypical. Objects can be created directly on the basis of other objects, adopting all their characteristics.

    Java is a standalone language. This means that by limiting yourself to only this, you can write a full-fledged program. JavaScript is primarily used in combination with the markup and styling languages ​​HTML and CSS.

    One of the important aspects of programming is multithreading. In simple words, in a normal situation, all the work is done step by step. If one method is running, then until it completes, the next one cannot run. In some cases, this is inconvenient – imagine if, when downloading a file from the Internet, you could not continue browsing the web, but had to wait until the process completed. But different languages ​​provide tools to overcome this problem.

    Java supports multithreading. Processor cores can perform multiple tasks simultaneously, distributing memory between them as optimally as possible.

    JavaScript applications do not have this capability. There are methods to simulate this mechanism to optimize performance, but the conventional threading approach is not available.


    Let’s move on from technical details to other aspects. How many people use each language? According to  SlashData , the Java community has 9.6 million developers, while JavaScript has a record 16.4 million, more than any other language.

    Java is used on 56 billion devices around the world, and it consistently occupies high positions in popular ratings.

    JavaScript is  indispensable for the web – 97.8% of sites use the language for programming the client side.


    Both languages ​​are considered relatively easy to learn , at least at a basic level. They are high-level, have detailed documentation and many resources and communities where you can find support. To a certain extent, JavaScript may seem easier at the beginning due to its less strict rules, but on a deeper level, each language has its own complexities.

    As you can see, Java and JavaScript are completely different languages. So if you’ve been thinking about adding a new technology to your skills, now you know what to choose based on the area you’re interested in expanding into. Or study both – Full Stack developers are also in  trend .