Java Developer Roadmap 2026: From Basics to Production

 

Transcript:

This is a Java developer roadmap for 2026. And contrary to the previous roadmaps, this one is for other people. This one is for those of us who are only beginning, who want to choose a language, and who probably want to understand what they will need to learn before they become an actual Java developer in enterprise. Obviously, it is impossible to learn everything in this video in one year, but you can totally learn the basics and get a general understanding of many other topics. Also, this roadmap will hopefully provide you with some materials you could use while learning and actually some future perspective.

Hi, my name is Pasha. I'm a Developer Advocate for BellSoft, and I have more than 15 years of experience in Java development. I wish I had something like this video at the beginning of my career. We will have a PDF version of this roadmap published down below in the description. So if you don't have time or you forget about the video, you can always get back to the PDF version of the roadmap and see what's ahead.

I split this roadmap into eight levels like an arcade game. And you might find that the last of them is much more complicated than the first one, even though starting is usually the hardest part. So let's start from the first level.

Fundamentals. Everything obviously starts with syntax. You should learn variables, functions, data structures, operators, and control flow, for example loops, ifs, elses, and so on. And you should know such a basic structure as an array.

Then, after you know the basics, you will go to safety. And safety is essentially about two things in Java. First, it's about exceptions, how you should throw them and how you should handle them. And second, it's about classpath. Classpath is exceptionally important in Java. Classpath defines what is available inside your application and what is loaded there.

After you learn the syntax basics, you move to the core toolchain: Java, javac, and many other tools included in the JDK. Then, if you don't know what OOP, object-oriented programming, is yet, you will have to learn it to understand the idea of classes, and to understand the four pillars of object-oriented programming: encapsulation, inheritance, polymorphism, and abstraction. And in Java, you will also have to understand the difference between static and instance methods.

If you need reference material for this level, you may want to look at the book by Cay Horstmann called Core Java. The book is immense. It's huge. Probably even reading it would take longer than a year. But you don't need all of it. You need only the parts you are currently interested in. If you hesitate about which number type you should use, look at Core Java. If you don't know what Runnable is, look at Core Java. It has a lot of answers, but it doesn't mean that you should remember them all by heart.

This book also covers level two. Let's jump to it. Level two is the standard library. The standard library starts for you with the collection framework. You need to know what lists, sets, and maps are, and what generics are. They are used everywhere in the collection framework.

After that, you probably would like to learn about modern Java, because Java 25 is significantly different from Java 8, and you would like to learn about lambdas, the Stream API, optionals, and records. Now there are several essential APIs you should know too. For example, you should know about StringBuilder, File I/O, and NIO. You should know the Date-Time API and Math, probably the main class to work with mathematical abstractions.

If you need more books at this point, I have one more for you. The book Effective Java tells you a lot about how to use these things correctly. So you won't be going into the selection between List and Set blindly. You will know exactly what you are doing.

Now I have to say, if you really mastered level one and level two, you're already an amazing Java developer. You know how to use Java, you know how to use it properly, and probably you could solve almost any task with it. But still, the development world is so much more than just writing code, right? We should build the code, ship the code, and so on. And level three, development and build tools, is about your mastery of tools.

And obviously, you should know build systems for Java. Currently, there are two main systems: Maven and Gradle. There are others, like Bazel, but they're much less popular, so probably you don't need to spend time on them.

Obviously, you can't write code in enterprise without using version control, so you have to use Git. Git is everything, and it's everywhere. And the main hosting for Git is either GitHub or GitLab these days. Many companies have their own storages, but if you know GitHub, you already can work with the whole, or almost the whole, Java open-source ecosystem, which is an amazing entry to your career.

Then, to actually write code outside of Notepad++, you should probably use an IDE. You will be much more comfortable with it. And in my opinion, there is only one IDE you should look at: IntelliJ IDEA. It is free for personal use, and it will allow you to do all the things you need to do with Java. Also, the refactoring and debugging capabilities of IntelliJ IDEA are just amazing. There are many talks about it. Just look at them.

If you need more reference literature, then for Git you have to read the Git SCM book. For other things like Maven, Gradle, and IntelliJ IDEA, you probably would like to read the reference documentation.

Now when you know all the basics, we can move to advanced topics. Obviously, most parts of modern enterprise software couldn't live without data persistence, and usually we are talking about relational databases. So you should learn them. You should have an understanding of what SQL is, what create, update, select, delete, and insert are, and so on.

When you have this understanding, you will be able to use JDBC, which is Java Database Connectivity. It's a layer of Java that allows you to work universally with almost any relational database. And then you would probably prefer to dive into ORMs, object-relational mapping. It's a very interesting concept. It kind of allows you to abstract away from the database.

You may want to ask, "Pasha, but you just said we have to know our databases." Yes. And that's why you don't start with Hibernate. That's why you start with JDBC and SQL, to understand how Hibernate works under the hood and to be able to debug it if something goes wrong.

As always, I have a book to recommend to you regarding this topic. Read Java Persistence with Hibernate. It's an amazing book about Hibernate and how to use it in production. Also, for Hibernate and for all databases, please refer to their reference manuals.

It would be virtually impossible to write a huge enterprise application like, probably, your bank has without knowledge of the enterprise web stack. So this is our next level, level five. First, you have to learn about dependency injection and inversion of control. This is probably the cornerstone of the whole rest of the way of writing Java applications.

After that, you would like to learn several projects. Mostly you are interested in Spring, particularly Spring Web to create web applications, Spring Data to work with databases and different storages, and Spring Security, because every application should be secure, especially enterprise ones. Or probably you would like to look into Jakarta EE, which used to be the Java standard back in the day. It's not anymore, but it's still developing rapidly. And of course, there are counterparts of Spring technologies there for web, persistence, and security.

And also there are many other frameworks, smaller ones, not that popular, like Quarkus, Micronaut, maybe Javalin. You can look at them, but when you know the basics of Spring, and probably not only the basics but some more advanced topics too, you are essentially good to go. You can learn everything else when you need it.

To be honest with you, I have never read a book on Spring, but I know that Spring in Action is good, and also the reference manuals for all Spring technologies are amazing.

But you know what? It's not important how good you know Java or how well you know Spring. What is important is that everyone makes bugs. Yes, me too. Yes, everyone. And to fight bugs, we need to be able to write tests.

So this is our next level, level six: testing and code quality. It all starts with unit testing. The main framework for unit testing in Java is JUnit. And you will also need to know a couple of additional ideas about unit testing. You will need to know what mocking is and what faking is.

Then after unit testing, you also need to know about integration testing. There is a huge argument about what we call integration testing and what component testing is. Not important. You need to know something about integration testing and how to do it in Java, probably how to do it with Spring.

And after that, you probably would like, or it would be curious for you, to learn about advanced testing techniques like, for example, mutation testing, property-based testing, or behavior-driven design. This is not essential, but it might be interesting and might be very useful in some kinds of applications.

After you killed all the bugs, you will have to ship your software to production. And this is our level seven: deployment. For deployment, you will need to know at least a couple of concepts: containerization. In particular, you need to know Docker. And by the way, Docker helps a lot when you have to deploy software.

You will also need to know things about CI/CD, continuous integration, and continuous delivery. There are two major tools these days that are the most flexible and the most capable, in my opinion. They are GitHub Actions and Jenkins. By the way, Jenkins is written in Java.

So, you could notice that with these levels we abstract further and further away from Java. Level seven almost doesn't have anything in common with Java. Yes, you need to know some things, but it is more about production than about code itself.

Level eight is different. I will only say a couple of words about level eight. Level eight is about concurrency. Concurrency in Java is complicated. Yes, Java was created with multithreading in mind. It is done amazingly well. But you still need to learn concurrency because in the package java.util.concurrent there are many, many concurrent data structures. They all are not trivial, or many of them are not trivial.

Usually, you can't just use them. You need to understand what their trade-offs are and what their benefits are. You also need to know many of them just in case, because sometimes it happens that you think you can use something, but you actually can't, and it would lead to errors in your software.

I won't read you a huge lecture on concurrency. It's probably too early. But when you are at this stage, and I'm still there, by the way, I'm not sure if I know concurrency perfectly. I actually know that I don't. Well, there is one book I can really recommend: Java Concurrency in Practice. I don't know any better book on Java concurrency, to be honest.

If you mastered level eight, first, congratulations. The princess is in another castle. Second, congratulations, you're much better than me, because I'm not sure if I mastered them all, but I'm trying. I'm really trying almost every day. Third, if you're at this point and you still remember this video, probably at least a year has passed. Come here, leave a comment, say thank you, and I will say thank you right now. Thank you for your attention. If you liked the video, like the video, subscribe to the channel, drop a comment down below, and with this, Pasha out.