2023 Java roadmap for developers

Beginner to advanced Java roadmap

Software development is one of the most rewarding careers in the world of IT.

Java is one of the most ‘in-demand’ programming languages around.

If the Java platform calls to you, and you want to immerse yourself in the world of Spring, Jakarta EE, Maven, Jenkins and Android development, here’s the 2023 Java Roadmap for developers.

Roadmap for Java

Here are the steps you’ll want to follow on the 2023 Java developer career roadmap:

1. Learn the fundamentals
2. Get object-oriented
3. Install the JDK and an IDE
4. Dig deeper into the API
5. Build out your core Java skills
6. Master collections
7. Get Functional
8. Straddle the middle-tier
9. Learn Java DevOps tooling
10. Study the JVM and the Java platform

Learn the fundamentals of Java

At their core, all programming languages are the same.

All a computer program can really do is:

• Manage data through the declaration of variables
• Perform conditional logic with if else statements
• Do all of this repeatedly and fast with iterative loops

Your first stop on the Java developer’s roadmap is to learn these fundamentals.

Learn Java fast

It’s easy to get started.

You don’t even have to install an IDE or the JDK. You can learn the basics of Java online with sites like Onecompiler and Replit.

You can make learning Java even easier if you use JShell.

You’ll find it much easier to learn Java through the JShell scripting environment than by creating Java apps with the intimidating ‘public static void main’ method declaration in them. JShell will make your learning journey much easier.

Once you’re setup on Replit or Onecompiler, create some basic applications that force you to learn loops, conditional logic and variable declarations. Popular projects that drive the learning include:

• The number guesser
• Rock paper scissors
• A to do list
• A simple calculator

When you’ve got the fundamentals under your belt, you’re ready to learn about object-oriented analysis and design.

Object-oriented programming concepts

In terms of loops, variables and conditional statements all programming languages are pretty much the same. Where programming langauges differ is how they organize data.

Java is an object-oriented programming language, which means it organizes data into components known as object. That means the next stop on the 2023 Java developer’s roadmap is to learn object-oriented analysis and design.

Java OOA&D concepts

In Java, object-oriented programming means organizing your data into:

• Classes
• Interfaces
• Enumerations
• Records

To really understand how objects work, you’ll also want to learn how to apply object-oriented concepts such as:

• Abstraction
• Encapsulation
• Inheritance
• Composition
• Polymorphism

With these components and concepts under your belt, you’ll be an object-oriented expert.

The development of object-oriented programming skills is an important stop on the Java roadmap for developers.

Install the JDK and an IDE

You can delve deep into the fundamentals of Java using online compilers and tools, but there does come a time when you need the power of an IDE at your disposal. That takes you to the next stop on the 2023 Java roadmap for developers.

Install the JDK

At the very least, a Java developer should have the latest long-term support (LTS) release of Java installed on their machines, along with a modern IDE such as:

• Eclipse
• NetBeans
• Visual Studio
• IntelliJ by JetBrains

Unlike the other three, IntelliJ isn’t free, but it’s widely used in the corporate world, and there are trial licenses available.

If an open-source alternative is more your style, try any one of Eclipse, NetBeans or Visual Studio.

Explore the JDK

Once you’ve got the JDK installed, you should dig around in the \bin directory and explore the various tools packaged there like:

• The javac compiler
• The Javadoc generator
• The JShell editor
• The javap class disassembler
• JStat for metrics gathering
• The Java Flight Recorder

You’ll be amazed at how many full-featured performance, monitoring and troubleshooting tools come bundled with the JDK.

Explore the standard Java APIs

With the assistance of a full-featured IDE, the next stop on the Java developer roadmap is the exploration of the many standard Java APIs that come packaged with the JDK.

With the hundreds of packages and classes that come standard with the JDK you can:

• Create your own web server with the java.nio package
• Access a database with JDBC components
• Create simple windows apps with Java Swing
• Create threaded apps with the concurrency APIs

Very few programming languages come with as many APIs as Java.

Enjoy these APIs and use them to further your knowledge of Java programming.

Strengthen your Core Java skills

After rushing through the standard APIs with an IDE, it’s time to get back to basics and focus on some core Java constructs including:

• generics
• modules
• exception handling
• RegEx

Java generics

Java’s type system can be overwhelming at the start, and most developers gloss over Java generics at the onset of their learning.

However, a strong knowledge of generics in Java will give you a deeper understanding of how Java works, and more importantly, how Java differentiates itself from languages like Python and JavaScript.

Java modules

Java’s module system is relatively new, and it’s often skipped as developers learn the language. Modules tend to be an unnecessary distraction at the start, yet they are an incredibly powerful feature of the Java platform, and developers are wont to learn it.

Java Exception Handling

Exception handling another topic new learners often put off at the start.

Developers need to learn the fundamentals of the try…catch…finally block in Java, along with helpful syntactic sugar such as:

• Try with resources initializations
• Closeable interfaces
• Suppressed exceptions
• Checked vs Unchecked exceptions
• Errors and RuntimeExceptions

Regular Expressions

To search and parse text, nothing beats RegEx. However, Regular Expression do require a day or two of practice to get the syntax right.

Learn RegEx.

Every software development team needs at least one member who knows how to find all the email addresses and phone numbers in a gigabyte of unstructured text.

Master the Java Collection classes

Much of the day-to-day work we do as Java developers boils down to list processing.

Java has an extensive Collections API with a variety of specialty components that solve unique data processing problems.

Collection related concepts you’ll want to familiarize yourself with include:

• ArrayLists vs Vectors
• HashMaps vs Hashtables
• Lists vs Sets

Individual collection classes you’ll want to learn about include:

• Iterator
• Dictionary
• LinkedList
• Queue
• Dequeue
• ListIterator
• SortedSet
• TreeSet

List processing is an important topic for Java developers and must be included on any roadmap for Java programmers.

Get functional

The introduction of functional programming into the Java programming language, along with a variety of components that take advantage of the functional programming paradigm, has been the most drastic change to come to the Java programming language in decades.

To get familiar with functional programming, first learn how lambda expressions work in Java.

Then get familiar with the functional interfaces often used in a lambda expression, including the:

• Consumer
• Supplier
• Predicate
• Function

These interfaces, and derivatives of them, now pepper the entire Java landscape. Familiarity with them will make it much easier for you to pick up more advanced Java concepts like Streams.

Master Streams

As was mentioned before, much of what a developer does is manipulate collections of data.

We also mentioned how a giant change in the Java platform was the introduction of functional programming.

When you combine the two, you get the Java Streams API.

Java Streams API

A Java Stream is a special pipeline for data processing, filtering and aggregation.

Java streams are incredibly efficient, incredibly powerful and incredibly intimidating when you first encounter them.

However, Java streams are actually fairly self-explanatory when you understand the concepts behind them.

Some of the key Streams API methods you’ll want to learn to solidify your understanding of Java Streams include:

• count and distinct
• findFirst and findAny
• peek and filter
• map and Reduce
• noneMatch
• min and Max

Modern Java development requires an in-depth knowledge of Streams. This is an important stop on the 2023 Java roadmap for developers.

The Java roadmap for developers is not complete without a strong understanding of the Java Streams API.

Jakarta EE and Spring Boot

Java has always been a major contender in the middle-tier space, and with the industry-wide shift to microservices, Spring Boot and the Jakarta EE frameworks are more relevant than ever.

Jakarta EE is the evolution of the Java EE middle-tier development framework. Oracle recently handed Java EE over to the Eclipse Foundation, which is why it is now known as Jakarta.

Within Jakarta EE you will find important enterprise APIs, some of which data back to the days of J2EE, including:

• Context and Dependency Injection
• The Java Persistence API (JPA)
• Servlets and JSPs
• Web APIs for RESTful web services
• JavaServer Faces
• The Validation API

Spring Boot microservices

Spring Boot is an open-source framework designed to help Java developers quickly build cloud-native microservices.

Some Spring Boot packages simplify integration with JakartaEE APIs like JPA, others simplify access to core Java APIs like JDBC, while others, like WebMVC, provide an entirely independent alternative to JakartaEE APIs like JavaServer Faces and JavaMVC.

Spring vs Jakarta

The problems Jakarta EE and Spring Boot solve are similar, and with knowledge of one, a Java developer could quickly get up to speed on the other.

Which one a developers chooses to learn first isn’t an issue, so long as a developer commits to learning one of them.

Due DevOps diligence

DevOps is all about motivated developers who share an Agile mindset using the best tools available to create new processes that aid in the continuous delivery of software.

To be a successful Java developer, you need to know the tools that drive DevOps on the Java platform.

The most important Java DevOps tools in use today include:

• Git and GitHub for source code management
• Maven and Gradle build tools
• Jenkins for Continuous integration
• JUnit and Mockito for testing
• SonarQube for static code analysis
• Artifactory for repository management
• Docker for containerization
• Java Mission Control for runtime monitoring
• Cloud computing with GCP, AWS and Azure

The combination of these tools and technologies allows developers to move beyond continuous integration into the modern sphere of continuous delivery and eventually, the continuous deployment of software.

An understanding of DevOps is an important part of the career roadmap for Java developers.

Understand the Java platform

Good Java developers know the Java programming language.

Great Java developers understand the Java platform.

To be a great Java developer, learn about the intricacies of the Java platform, including:

• How Java allocates memory
• How garbage collectors work
• How to convert Java to WebAssembly
• How to decompile Java code
• How the JVM schedules threads
• How object serialization works

An understanding of these topics will give you a greater appreciation of how the Java platform works, which will help you troubleshoot low level JVM issues when they arise.

The last stop on the Java roadmap for developers is to understand how the JVM works.

The 2023 roadmap for Java

There’s a lot to cover on the 2023 Java roadmap for developers, but it’s worth it if you want a rewarding career in the software development industry as a Java programmer.