OpenJDK Java

My main use case for OpenJDK Java  is for various development purposes including desktop, web, integration patterns, interoperability, and everything that is usually included in standard enterprise projects and small demo examples that I use in teaching while instructing students at my courses.

The best features OpenJDK Java  offers depend on the version. Usually, the last few versions included virtual threads and all the optimizations that benefit applications including Spring  applications, etc. Nowadays you don't need to rely on platform threads. You can use virtual threads without a problem and create them in vast numbers, not just hundreds, because asynchronous applications are very important for creating an environment in which you can be responsive, and especially in this AI age where you can combine everything together and try to provide your users with the best features and best capabilities of your system. Of course, the latest version includes the Vector API. I'm looking forward to actually using the best features related to that and all those small perks that are added to every single version, such as lambda expression optimizations, HTTP client, JavaFX that I use, and everything that helps you to be productive and to follow the best practices such as SOLID principles, design patterns, and clean code.

OpenJDK Java has positively impacted my organization because the word open actually opens everything more to the community. Usually people don't want to be vendor-locked. That's why they need this opportunity to choose their own platform to create an environment where they feel the most comfortable and of course, the most productive. Every next version of OpenJDK, for example, the last few years we experienced optimization in garbage collectors, etc. Someone can also include their own garbage collector or choose from the list of available and supported garbage collectors. They can have this support that will give them full control over their environments. Everything that is added to the stack every six months also makes the whole community vibrant. We eagerly wait for those short-term releases every six months, but at the end of the day, the latest versions are those that have the most impact to the community.

I think that we need to follow the latest trends and include even more optimization in the language to match the best performing languages so we can get more with less code because Java often requires some kind of boilerplate to achieve many things, but other languages don't require that. This is perhaps the only thing that will naturally evolve in the future. Also since Java was released in 1995, nowadays we celebrate 30 to 31 years of Java existence on the market. There are certainly things that can be optimized. This release cycle every six months is a good one, so I think newer features will be added and of course, older features will be removed. For example, I really don't prefer to use primitive types such as int, long, short, and boolean. I would rather use records or reference types. This could be something that might be more promoted to actually use other reference types rather than using primitive types. I understand how deep this is within the language, so it cannot be extracted or cut off from the platform. However, it's our responsibility to promote the best practices and to use, for example, optional types instead of null references to avoid null pointer exceptions. This is something I really appreciate in Java because avoiding common pitfalls and mistakes helps developers to be more productive.

I have been using OpenJDK Java since I started programming in 2003 when I was a student.

I would like to see some alternative tools that will help developers to start development with AI assistance because JetBrains IntelliJ is something that is really powerful, but when you are no longer a student, you need to pay for the tooling. Before, let's say 20 years ago, we had Eclipse or JDeveloper environments, but they are not keeping pace with the competitors. That's why this open keyword should also popularize the whole Java enterprise and community, etc. It will help to have a tool that will be competitive to the other elements because, for example, we had the Scene Builder for JavaFX that was maintained by Oracle, but they abandoned it. So this parallel thread, let's say Gluon JavaFX is now actually producing good results. That's why this branding is very important. If you actually stand behind a tool that will be created for this new era of development with the help of AI and live coding, it could help the platform to be more popular and of course, involve more than 10 million developers. Although Java is already over 30 years old, it will still be a main competitor on the market. For all enterprise development solutions, Java as an open-source technology could still be the number one choice and stay for a long time as number one.

An example of how I use OpenJDK Java in my teaching and enterprise projects is that since everything I teach is related to Java, I create an object, for example, in the IntelliJ JetBrains environment. Then when a new Java version is released, perhaps version 25 or 26 every six months, I download it through this tool, JetBrains IntelliJ, and configure my project, mostly Spring  projects or vanilla Java projects without any specific frameworks to establish the basic functionality, and then I start developing all the features that are required for this purpose.

At the end of the day, Java is a platform and many open-source libraries and projects are added to the technology stack and then we are implementing enterprise applications, web applications, or even console applications just to show that this is something that can cover everything. With AI, it's much easier because the best models are using the latest Java versions without any problems, so you can immediately be very productive and at the end of the day, you can deliver your application much faster than you could five or six years ago.

I want to show many examples of performance, measurements, reports, and automation such as unit testing, CI/CD, and especially integration with AI regarding how I use OpenJDK Java in my teaching and development.

The efficiency of virtual threads is the first thing that comes to mind when I talk about how virtual threads or any of these features have changed the way I and my students develop applications. Instead of creating platform threads that are very heavy for the system because the memory footprint is 1 MB to 2 MB per thread, with virtual threads, you actually have a footprint of 1 KB, which means that you can create many threads and they can be synchronized, especially if you use asynchronous operations or prefer to have non-blocking changes to every resource that you are contacting with. This is something that can be done much more easily and you can create a pool of threads that you use efficiently, so you can be much more productive when you use those things. Of course, your system can utilize the hardware resources much more efficiently and that's why this is the future of asynchronous parallel development. For example, when you synchronize virtual threads with your main thread in JavaFX UI, you can actually create something that will run in the background without taking too much processor time and actually increase the responsiveness of every application.

I want to highlight especially the newest features that are included in the latest releases, such as the Vector API, because I tested the Vector API a few years ago when it was in the incubation period. It was still promising to actually use some features of CPUs to even better optimize the processing of large data. Especially nowadays we use many datasets when we prepare the datasets to train our LLM models. This is something I would like to highlight and I'm looking forward to getting the final version so I can play with it in my own use cases.

My advice for others looking into using OpenJDK Java is that they need to compare their own solutions to OpenJDK Java and then decide for themselves because it's very important to have a choice, not to be vendor-locked. You should have a choice and compare how good this is accepted, how easy you can actually get all the information, and how good it is accepted across the AI landscape. If the AI generates many examples that can be easily integrated or run on OpenJDK Java, that's the way to go. I give this review a rating of 9 out of 10.

I have been using OpenJDK Java  for around two years, mainly for building backend services and APIs in microservices architecture.

My primary use case with OpenJDK Java  has been building scalable backend systems, including REST APIs, async job processors, and event-driven services.

One example is a booking system I worked on where we handled around 50,000 daily requests using OpenJDK Java with proper JVM tuning, which reduced API response times by about 30% and improved throughput significantly without increasing infrastructure costs.

Beyond APIs, I have also used OpenJDK Java for batch processing jobs and background workers.

The best features of OpenJDK Java in my experience include write-once, run-anywhere capability thanks to the JVM, along with powerful performance optimization and garbage collection tuning options for backend systems.

I have seen significant improvements in system stability and resource utilization thanks to OpenJDK Java's garbage collection and JVM tuning capabilities. For instance, in one project, we were able to reduce memory-related issues by over 50% by fine-tuning the JVM's garbage collection settings.

The open-source nature of OpenJDK Java is a significant advantage, giving flexibility to choose different builds such as Amazon Corretto  or Red Hat builds. Additionally, the frequent release cycles help us adopt new features quickly.

OpenJDK Java has positively impacted our organization by helping us standardize our backend stack across teams, making onboarding easier. New developers could ramp up faster since Java and OpenJDK Java are widely known and well documented.

One area that could improve OpenJDK Java is official enterprise-grade support. While community support is excellent, sometimes companies still prefer vendor-backed guarantees.

The documentation for OpenJDK Java is good overall, but debugging JVM-level issues can still be complex for newer developers. Better, simplified guides around memory tuning and garbage collection would help.

I have been using OpenJDK Java for around two years, mainly for building backend services and APIs in microservices architecture.

OpenJDK Java is extremely stable. We have had services running for months without restarts, handling high loads without any major JVM crashes.

Scalability is one of OpenJDK Java's strongest points. With proper JVM tuning and containerization, we scaled services to handle 3x traffic spikes during peak hours.

We were initially using Oracle JDK but switched to OpenJDK Java due to licensing costs and flexibility concerns, as OpenJDK Java offered the same core functionality without the restrictions.

The experience with pricing, setup cost, and licensing for OpenJDK Java is straightforward and completely free since it is open-source. We usually install it via package manager or Docker  images, making onboarding new services quick.

The ROI has been strong with OpenJDK Java due to zero licensing costs, stable performance, and reduced operational overhead, overall improving efficiency by around 25% across backend teams.

We cut the licensing cost almost completely by moving from Oracle JDK to OpenJDK Java, saving roughly 20 to 25% annually on infrastructure.

Before choosing OpenJDK Java, we evaluated other options including Oracle JDK and some JVM alternatives, but most were either expensive or less flexible compared to OpenJDK Java.

I have found that the learning curve for new developers adopting OpenJDK Java in our team is relatively moderate. They typically already have a background in Java, allowing them to get up to speed quickly and start contributing to our projects with some guidance and resources.

I have had a smooth experience integrating OpenJDK Java with other technologies, particularly Spring Boot  and containerization tools such as Docker . OpenJDK Java works seamlessly with Spring Boot , allowing us to develop and deploy applications quickly and efficiently.

I handle security and updates for OpenJDK Java by regularly checking for updates and applying them as soon as possible, while also making sure to follow best practices for secure coding and configuration. I have found that using tools such as Docker and Kubernetes  helps streamline the process of keeping our deployments up to date and secure.

We monitor and manage the performance of our applications running on OpenJDK Java using tools such as Java Mission Control  and VisualVM, which provide detailed insights into memory usage, CPU usage, and other key metrics.

We have found OpenJDK Java to be highly performant and reliable compared to other Java distributions such as Oracle JDK, and in some cases, even more stable due to its open-source nature and community-driven updates. It has consistently delivered high-quality performance and reliability across various applications and deployments.

We handle version upgrades with OpenJDK Java by regularly checking for updates and applying them as soon as possible to ensure that we have the latest security patches and features.

Since OpenJDK Java is community-driven, we rely mostly on forums and documentation. For critical systems, we sometimes use vendor-supported builds for SLA coverage.

I would recommend starting with OpenJDK Java if you are building backend systems, as it is cost-effective and production-ready. I suggest investing some time in understanding JVM tuning early on.

OpenJDK Java is a very mature and reliable platform, giving enterprise-grade capabilities without the cost overhead, making it an excellent choice for most backend systems. I would rate OpenJDK Java a nine out of ten.