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John Selawsky
John Selawsky

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How Long Does It Take To Learn Java If I Know JavaScript?

IT is doubtlessly a rapidly changing field, and the only chance to remain an in-demand specialist is to always be in the know of all changes and keep up developing. That is why the coders who know two or more programming languages and are constantly expanding their knowledge base are especially wanted among employers.

Because knowing several programming languages is trendy today and I am often approached by my students with requests like “How long does it take to learn Java if I know JavaScript?”, I’ve decided to write an article covering that topic.

Why Should You Master Java if You Already Know JavaScript?

Choosing the language to switch to is sometimes tricky, and coders are often looking for proves that the switch is worth making their effort. To facilitate your choice of the right language, I’ve collected some evidence on why Java is a good way to go if you already have JavaScript mastered.

Broader Skills

Knowing more than one programming language can be compared to the work of a handyman, who has a bunch of tools with which he can perform various tasks. Similarly, programmers with two or three languages under their belt can build complex projects. Given the problems you want to solve with a project, you can pick up the language (from those you have at hand) that can surely help you with resolution.

Greater Opportunities

The more knowledge and skills the programmer has, the more employment opportunities and career prospects he or she gets. Today, many companies are looking for universal developers. As a “monolingual” programmer, you significantly limit yourself to only a few roles in projects, while knowing two or three programming languages provides you with multiple career paths and lets you land a dream job.

Higher Revenue

The more languages you know, the more you can earn to support yourself — the companies are willing to pay more to “multilingual” specialists. Back in 2018, Coding Dojo analyzed job listings in Fortune 25 companies and found out that none of them worked with a single language. They adopt polyglot codebase, and hence are interested in specialists with more than one language at hand.
Being proficient in more than one programming language lets you remain flexible and quickly adapt to technology shifts that happen in the programming world quite often. One technology replaces the other and those languages that have been less sought-after suddenly become more rewarding than others. So, knowing many technologies makes it possible for you to stay ahead of the competitors and ensures upward mobility.

Last but not least benefit of knowing two or three technologies is that you can manage a team of coders working in different languages and bring more value to a project than a “monolingual” specialist.

Java vs JavaScript: What Are the Principal Differences?

Java and JavaScript are often confused and thought to be related to each other. But even though there are some similar features between them, these two languages still play dramatically different roles in programming. So, let’s find out what distinguishes them.

  • Use cases. Java is mainly used for backend, Android, and desktop app development, while JavaScript basically focuses on making the web more interactive and creative.
  • The way language programs are executed. Java compiles code being executed on JVM. This means that object types are checked on compilation and classes and methods are linked before execution. JS code doesn’t require compilation before execution. All type checks and linking are performed on execution time by browser/interpreter.

Java vs JavaScript Differences [Comparison Table]


How Long Does It Take to Learn Java if I Know JavaScript?

The transition from JavaScript to Java could be both easier and harder than from C++, for instance. The time it may take to learn Java depends on different factors: your studying pace, coding background, or willingness to do the hard work.

If you set aside a few hours for studying every day, it may take you up to two-three weeks to grasp an idea of principle concepts and start creating something basic. However, if you want to start working with Java at your earliest convenience, it’s all up to you — give your day and night, and you’ll be able to apply for your first Java programmer position at short notice. The sky’s the limit.

Sources to Master Java

For a more engaging and fast learning process, there are multiple interactive Java programming courses on the web. But, I would highlight a few of my favorites that should be interesting for you.


CodeGym is a single-language online course focused on providing you with as much practical experience as possible. It offers to complete 1200+ coding tasks to master Java. The tasks can promptly be verified by the virtual mentor (AI, not a person), so you can get recommendations on what to improve in your code. You can also create your own version of one of the classic video games and hence end up the course with your first small project.

The Complete Java Masterclass

This Java course by Udemy is perfect for students who already know another programming language and want to add Java to their skills as well. The program allows mastering Java without a hassle. It covers all important features and concepts from Java fundamentals to more advanced topics, such as OOP, Java collections, lambda expressions, multithreading, etc.

Java Programming for Complete Beginners

When mastering Java, you will surely get confused because of the differences between Java and JavaScript. This is where you might need a course that would sort things out about a new language. A Java course for complete beginners is one of them. It is created following the modern learning approaches, so you will learn Java step-by-step, starting with the language basics and step up to more advanced topics. The course creator promises that you will polish up your Java skills in a bit more than 250 steps.


Codewars is another gamified learning platform that makes it possible for you to learn Java from scratch. While mastering it, you will train on the challenges called kata with the other students. Upon completing every next level, you will gain honor and rank. Codewars also allows you to create your own kata and challenge your peers.

Java Certification by Duke University

This Coursera specialization will help you acquire the basics of Java language. You will learn to code in Java, improve your problem-solving skills, learn new data structures, and even solve real-world problems using Java classes. Apart from that, you will have a chance to brush up on foundational JavaScript programming concepts.


Unlike many other gamified learning platforms, Cyber-Dojo encourages you to improve your programming skills rather than finishing the coding game as soon as possible. The platform comes with challenges and exercises that allow practicing more than 30 programming languages, including Java. The students can practice individually or join groups. Every offered task has detailed instructions on how the end result is supposed to look like.


CodeChef platform is known for its coding contests and challenges run twice a month. Users can practice over 50 programming languages by competing with other programmers. CodeChef is an ideal place that allows specialists from the whole world to show off their programming skills and even win trophies. If you don’t want to participate in contests yet, CodeChef offers to join training sessions and discussions related to algorithms, binary search, and other tech topics.

Wrap Up

As long as you are already a part of the programming world and have a coding background, learning one more language will not be that tricky and time-consuming. If you already know JavaScript, it will not take you more than a month to master the basics of Java from scratch. So, set aside enough time for it and start learning today.

First published on Level Up Gitconnected.

Top comments (3)

elmuerte profile image
Michiel Hendriks

It takes a lot of effort as you need to unlearn a lot of bad things.
It's easier to move to Java if you come from a TypeScript background.
Moving from TypeScript to C# is easier than TypeScript to Java, main reason is that both TypeScript and C# were architected by Anders Hejlsberg (also the architect behind Delphi, where a lot of ideas in C# originate from.)

devlorenzo profile image

Cool article! Also because I know both of them 🙃

indian_pro profile image
Indian Programmer

Super Sir.