11 Things Java Programmers Should Learn in 2020

May 31, 2018 · 10 min read
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“Coffee in a cup with latte art in the milk in Lancaster” by frankie on Unsplash

Being a Java developer and the author of a Java blog, I frequently receive requests from Java programmers from all over the world asking how they can improve themselves.

In the past, I have shared my 10 tips to become a better programmer, and every tip in that article still holds true, but given that it’s a new year, I have decided to jot down new tips for Java programmers to improve themselves, enhance their knowledge of Java programming, and increase their value for future career growth.

So without wasting any more time, let’s see my nine ideas for Java programmers in 2019. You can take inspiration from these ideas to create your own goals.

By the way, folks, In this post, you will not only find what to learn but also where to learn as many of my readers often comes back to me that how they can improve certain skills, where to start, etc.

1. Learn Java Performance Tuning

In the last a couple of years, I have taken more than 50 interviews for senior Java developers, and one skill that I clearly see lacking is knowledge and understanding about JVM internals, GC behavior, and Java performance tuning.

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Learn JVM Internals

As your Java experience grows and you become a senior Java developer with more than 5–6 years of experience, it’s expected from you to know both the big picture and the small details about Java’s fundamentals.

If you can’t profile an application or cannot figure out why it’s slow or how to make it fast, then you should read a good book on JVM internals and performance tuning, e.g Scott Oaks’ best seller Java Performance the Definitive Guide.

I have been reading it for years and still refer to it whenever I get time. My goal is to read it again this year.

If you prefer online courses over books, then I suggest you take a look at Understanding the Java Virtual Machine series of courses on Pluarlsight, which explains memory management, class loading, Security, and Reflection.

2. Docker and Kubernetes

You’ve probably heard the buzz around Docker and Kubernetes and the impact it has on DevOps teams. You may have at first thought, “ahh, yet another new technology I need to learn”, but I will say that Docker is not just another technology but its truly a game-changer.

Along with Kubernetes, It’s one of the most important tools that you can learn and will stay with you throughout your entire career.

Nowadays, Docker and Kubernetes are used by almost every development team, whether it’s a large enterprise or a small startup. It’s safe to say that if you’re entering the workforce now, you’ll most likely brush up against Docker at some point.

In short, whether you are a junior Java developer or an experienced veteran of several years of experience, Having Docker and Kubernetes knowledge is essential for your career progression and job change. If you have already realized the importance of Kubernetes and looking to learn Kubernetes in 2020 then Docker and Kubernetes: The Complete Guide by Stephen Grider on Udemy is an excellent course to start with.

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If you prefer free resources, like free online courses, then you can also check out this list of free Docker and Kubernetes courses for Java developers to start your journey.

3. DevOps (Jenkins)

This is another area where I am seeing a lot of traction last year as more and more companies are moving into DevOps and adopting continuous integration and deployment.

DevOps is very vast, and you need to learn a lot of tools and principles, and that’s what overwhelm many developers, but you don’t need to worry. I have shared a DevOps RoadMap, which you can follow to learn and master DevOps, particularly Jenkins at your own speed.

This means if you are an experienced Java programmer with a passion for managing the environment, automation, and improving overall structure, you can become a DevOps Engineer.

If you are looking for some excellent resources, then Jenkins, From Zero to Hero: Become a DevOps Jenkins Master is a great course to start with, particularly for Java developers.

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4. Code every day for 2 hours

Another thing I noticed last year is that as your experience grows, you spend your time on coordination, replying to emails, being a catalyst, troubleshooting, mentoring, and generally being a project manager kind of person.

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Code, Code, and Code

What you left behind is coding, which is the single most important skill for a programmer.

If you feel that you are not doing enough coding, then make a resolution to code every day. At least, write something, be it on your project, an open-source framework, a library, or a utility.

Since starting is the most difficult thing, I suggest that any time you feel resistance, start reading and refactoring code for fun. You will enjoy that and, in the process, you will also write code.

You can also solve problems given in Cracking the Coding Interview, 189 Programming Questions. This will not only make sure you’re ready for an interview, but also improve your knowledge of data structures, algorithms, and programming logic.

5. Profile Your Java application Once a Month

This tip is attached with the first tip about reading a good book on JVM internals and or join a course on Java performance tuning. Btw, Just reading the book or joining a course will not be enough. You have to apply that knowledge in your live project.

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I suggest you profile your Java application, at least once a month and spend a good amount of time understanding and analyzing the results.

You can also take a heap dump of your Java process, or, if you had a recent crash, then take that heap dump and find out which object is taking most of your memory. Is there a memory leak in your Java application?

What is the cause? What will happen if other 100K new clients access your application? If you can answer all these questions comfortably, then you are in good shape. If you need some guidance on solving memory and CPU issues, I suggest you take a look at Understanding and Solving Java Memory Problems by Richard Warburton.

6. Participate in Coding Challenges

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This goal is, again, somewhat related to our second resolution — write code every day for 2 hours. Let’s face it, sometimes, you don’t have enough chances in your live project to code.

If you are starving for challenging code, then there is nothing better than participating in programming and coding challenges.

There are many websites on the internet that host programming challenges and give you the opportunity to test your skills, but TopCoder is simply the best.

If you are looking for some tough programming challenges, then you can also check out my list of good websites to practice coding.

7. Learn Network Programming in Java

One more thing I have learned from interviewing people is that Java developers need to improve their socket programming and networking fundamentals.

I have asked many questions from my list of Java networking programming questions, but most developers fail to answer most of them.

Some of them even struggle to outline the key differences between TCP and UDP, which I thought was too basic to ask any Java developer of 2–5 years of experience.

If you feel that you have not gotten enough opportunity to learn socket programming in Java or that you don’t need to because you are Java web developer working with JSP, Servlet, and JSF, then I suggest you read at least one good book on Java networking, NIO, and socket programming.

One book I highly recommend is TCP/IP Sockets in Java, Second Edition, Practical Guide for Programmers. It’s easy to read, interesting, and a good way to learn the fundamentals of socket programming.

8. Java 12 to 14

Last a few years have seen a couple of big releases, and one of them was JDK 12 and 13. I have yet to start with JDK 11, forget about 12, but this is the first thing I am going to look into in 2020.

If you want to learn new features of Java 9 like Jigsaw, Reactive Streams, API enhancements, etc., then the Java 9 MasterClass is a good course to start with.

Similarly for Java 10 features like var for local variables you can check a good course on Java 10 like The Complete Java MasterClass which is also most up-to-date and recently updated for Java 11 as well.

9. Spring 5.0

Another big release for the Java world in 2017 was Spring Framework 5.0. With lots of exciting features, e.g. reactive programming model and adoption of Java 8 and 9, Spring 5.0 adoption is going to speed up in 2019, and that’s why every Java developer should learn it. If you need some help, Spring 5.0: Beginner to Guru is a good course to start with.

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10. Spring Security 5.0

Another interesting release of 2017, which I am going to learn in 2020, is Spring Security 5.0. Spring Security 5.0 was a major release, and they rewrote a couple of modules and fixed several hundred bugs.

The most interesting part is the OAuth 2.0 module. Unfortunately, there are not many resources to learn Spring Security 5.0 at the moment, but thankfully, Eugen has updated his Learn Spring Security to cover version 5.0 and also added a new module on OAuth 2.0.

11. Unit Testing

If you want to become a better developer in 2020, then you should work on your unit testing skills. And not just unit testing, but automated testing in general. This also includes integration testing.

You can learn JUnit 5 and other advance unit testing libraries like Mockito, PowerMock, Cucumber, and Robot Framework to take your unit testing skill to the next level.

Mockito is really powerful and allows you to write a unit test for complex classes by mocking dependencies and just focusing on the objects under test.

If you are a beginner in unit testing and want to learn it in 2020, then the JUnit and Mockito Crash Course from Udemy is a good starting point.


That’s my advice! If you are a Java programmer with a couple of years of experience, you can also take inspiration from this list to set your goal. Some other things you can add to this list are learning Android, Docker, and Spark, as those are essential for any Java programmers.

I have purposefully kept this simple and achievable because I personally believe that small successes lead to big successes.

Setting small goals and achieving them is better than setting big, impractical goals and failing before kick-off.

So what are you waiting for? Write down your goals for this year and share them with us. At the end of the year, you can come back here and tell us about how much you achieved.

Other Programming Articles you may like

The 2020 Web Developer RoadMap
10 Reasons to Learn Python in 2020
10 Programming languages You can Learn in 2020
10 Tools Every Java Developer Should Know
10 Reasons to Learn Java Programming languages
10 Frameworks Java and Web Developer should learn in 2020
10 Tips to become a better Java Developer in 2020
Top 5 Java Frameworks to Learn in 2020
10 Testing Libraries Every Java Developer Should Know

Closing Notes

Thanks for reading this article so far. You might be thinking that there is so much stuff to learn, so many courses to join, but you don’t need to worry.

There is a good chance that you may already know most of the stuff, and there are also a lot of useful free resources which you can use, I have also linked them here and there along with best resources, which are certainly not free, but worth of money.

At the end of the day, you should have enough knowledge and experience about the things mentioned here.

If you like this article then please consider following me on medium (javinpaul) and subscribing to our publication.

If you’d like to be notified for every new post and don’t forget to follow javarevisited on Twitter!


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Written by


I am Java programmer, blogger, working on Java, J2EE, UNIX, FIX Protocol. I share Java tips on http://javarevisited.blogspot.com and http://java67.com


A humble place to learn Java and Programming better.


Written by


I am Java programmer, blogger, working on Java, J2EE, UNIX, FIX Protocol. I share Java tips on http://javarevisited.blogspot.com and http://java67.com


A humble place to learn Java and Programming better.

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