OpenJDK Java Reviews

My main use case for OpenJDK Java revolves around incoming financial documents such as PDFs, scanned balance sheets, and trial balances from clients. Apache Tika, which runs on OpenJDK Java, parses those documents and extracts the raw text. From there, we pass that cleaned text into our OCR pipeline using Tesseract and then feed it into our large language models for structured extraction, such as account mapping and compliance classification. OpenJDK Java gives a stable, reliable foundation for that parsing layer.

One thing worth mentioning about my use case is that consistency is crucial for us. Financial documents are sensitive, and we need reliable parsing. OpenJDK Java-backed tooling provides that stability. We run it on Linux servers in production for over a year with minimal issues. The concurrent processing capability is also important because we often batch process multiple documents at once, and it handles that load without memory problems. It is not just about parsing; it is about having a dependable backbone that we can trust in the production environment handling real clients.

The best features OpenJDK Java offers, in my experience, include stability, ecosystem maturity, and solid performance. The biggest one for us is stability; it runs consistently. Once we set it up on our Linux infrastructure, it is rock solid, with minimal downtime and no unexpected crashes over the year and a half we used it. The second is the maturity of the ecosystem. Because it has been around for so long, there are incredibly robust libraries built on top of it, with Apache Tika being the perfect example for our use case. Finally, performance matters. Once the JVM warms up, the throughput for document parsing tasks is consistent and predictable, which is essential when processing batches. Those three things make OpenJDK Java valuable for us in the production financial document space.

OpenJDK Java has positively impacted my organization by significantly reducing parsing failures. Before standardizing on this stack, we dealt with manual workarounds for document format inconsistencies, where approximately 10 to 15 percent of incoming documents required manual intervention. Once we locked in Apache Tika and OpenJDK Java as our parsing foundation, that dropped to approximately 2 to 3 percent. That is a huge operational improvement for our team because it meant less manual rework and faster throughput for our clients. On the speed side, document processing time became predictable; we could reliably process a financial document from ingestion to structured output in under two minutes on average, meeting our client service level agreements. From a cost perspective, being open source meant avoiding licensing fees, freeing up budget to reinvest in our machine learning models and infrastructure. For the team workflow itself, the sustainability meant our engineers spent less time debugging parsing issues and more time on higher-value work, improving our LLM extraction logic and building new features. There was a genuine productivity gain.

The JVM startup time is noticeable for lightweight, one-off document parsing tasks; that warm-up overhead feels unnecessary compared to a Python script that starts instantly. In a high-concurrency microservices environment where containers are spun up frequently, that matters significantly.

On the developer experience side, managing Java versions across different environments can get messy. We encounter situations where local development is running one JDK version, staging is another, and production is different. Without proper tooling such as SDKMAN or Docker, it becomes a coordination headache. Better built-in versioning and consistency would help. Regarding documentation, the OpenJDK Java documentation itself is solid but quite dense and assumes a certain level of Java knowledge. For teams coming from other backgrounds such as mine, which has a lot of Python and JavaScript experience, the barrier to entry is steeper than necessary. More beginner-friendly getting started guides would be beneficial. Additionally, the JVM baseline memory usage is significant. For resource-constrained environments or when running multiple lightweight services, that overhead adds up. Lighter JVM variants exist, but they are not as well-documented or easy to adopt. Better guidance on choosing the right JVM flavor would smooth that out.

I choose a rating of 8 out of 10 for OpenJDK Java because it could reach a 10 if the JVM startup time was dramatically reduced, perhaps through better default configurations or a lightweight default build for serverless and containerized workflows where speed matters. Secondly, a streamlined, unified approach to version management and environment consistency built in would help eliminate the need for juggling SDKMAN, Docker, and multiple configurations. Lastly, better memory efficiency out of the box would be ideal. If OpenJDK Java could run with smaller baseline footprints without sacrificing performance or stability, it would be a clear winner across more use cases. While it is the best choice for stable, long-running backend services and document processing pipelines, it has trade-offs for lighter, more distributed architectures. Fix those, and it would be a 10 out of 10.

I have been using OpenJDK Java for approximately one and a half years.

OpenJDK Java is stable. It has been rock solid for us in production. Over the one and a half years we have run it, we have experienced minimal unplanned downtime or crashes. The JVM itself is incredibly mature and well-tested across millions of deployments worldwide, which is vital for financial document processing where reliability is non-negotiable. We can depend on it.

On scalability, OpenJDK Java is good but has nuances. For our use case of batch document processing, it handles concurrent requests well, allowing us to process multiple documents simultaneously without memory leaks or performance degradation. The garbage collection is solid once we understand how to tune it. However, scalability depends on your infrastructure approach. Horizontally, we can scale by adding more servers running OpenJDK Java instances. Vertically, there are limits since the JVM's baseline memory footprint means we cannot plug unlimited instances on a single machine. For our document volumes and processing patterns, we never hit those limits.

The community support for OpenJDK Java is massive and active. When we encounter issues or have questions, Stack Overflow usually has answers. OpenJDK Java documentation itself is comprehensive, though it is dense and assumes some Java experience. For our team, coming from Python and JavaScript backgrounds, we had to do additional learning, but the resources are there. Specifically, the Apache Tika community has helped us greatly; the documentation for Tika is solid, with good examples, and the community forums are responsive. When we run into edge cases with parsing specific document formats, we typically find discussions or solutions within the community. The trade-off with open source is that we do not pay for dedicated support; however, we are also not dependent on the vendor support queue. We need to be more self-sufficient, but this approach works for our team. We troubleshoot, read documentation, check community discussions, and usually find answers within hours rather than waiting for support tickets.

Before standardizing on OpenJDK Java, we used a more fragmented approach. We had a mix of Python-based text extraction tools and some proprietary PDF parsing libraries. The problem was inconsistency; different document formats failed unpredictably with different tools. We ended up with manual workarounds, with team members extracting data from PDFs that the automated pipeline could not handle reliably. We switched to OpenJDK Java and Apache Tika because we required something battle-tested and stable for production use with financial documents. The Java ecosystem had proven libraries that could handle edge cases and unusual document formats that were giving us trouble. Tika's maturity and the JVM's stability made it the right choice, simplifying our tech stack significantly. Instead of maintaining multiple parsing tools across different languages, we have one solid foundation that reduces operational complexity. In hindsight, it was absolutely the right decision; the consistency and reliability improvements justified the learning curve my team had to undergo coming from a Python-heavy background.

We deployed OpenJDK Java on-premises. We run our OpenJDK Java infrastructure on Linux servers hosted in our own data center setup, which is important for our use case because we handle sensitive financial documents for clients including balance sheets, trial balances, and compliance data. Having on-premises infrastructure gives us direct control over data residency and security, crucial for client trust and regulatory compliance. We consider cloud options eventually; Docker containerization makes it theoretically portable to cloud environments if needed. However, we decided to keep it on-premises for data sovereignty reasons. The on-premises setup started well for us because our document volumes are predictable, allowing us to manage infrastructure costs directly. We do not need the auto-scaling flexibility that cloud would offer.

I have indeed seen a return on investment with OpenJDK Java, particularly in operational efficiency. As mentioned earlier, we reduced manual document processing interventions from around 10 to 15 percent down to 2 to 3 percent. That means our team of three document processors can handle approximately 40 to 50 percent more documents per week without adding headcount. Over a year and a half, that is a significant capacity gain without hiring additional people. On the cost side, being open source means we incurred zero licensing fees. For a financial document processing platform, that represents real money saved since commercial Java solutions would have cost us thousands annually in licensing alone. Development time is another critical metric; our engineers spend significantly less time debugging parsing failures and environment issues. I estimate we save approximately 15 to 20 percent of engineering time that would have gone to infrastructure maintenance, which we redirect toward building new features and improving our LLM extraction accuracy. The speed of processing a document from ingestion to final structured output in under two minutes means we meet aggressive client turnaround SLAs, translating directly to client retention and upsell opportunities.

We considered several alternatives before choosing OpenJDK Java. We explored a pure Python-based solution using libraries such as PyPDF2 or PDFPlumber for document parsing. The appeal was that our core application logic was already in Python, making for a simpler tech stack. The trade-off was in limitations with complex and scanned financial documents as those libraries are not as robust for edge cases. We landed on Apache Tika running on OpenJDK Java because it struck the right balance. It is mature, battle-tested for handling complex document formats, open source, meaning no licensing overhead, and the ecosystem is solid. Introducing Java into our stack meant stability and reliability gains justified the architectural decision.

If someone is considering using OpenJDK Java, I advise being clear about your use case; OpenJDK Java is excellent for backend services, document processing, and financial systems where stability and long-term reliability are crucial but less ideal for lightweight microservices or serverless workloads where startup time is critical. Secondly, invest in proper tooling from day one; use Docker for environment consistency, SDKMAN for Java version management, and set up proper JVM tuning parameters early. Do not underestimate this investment; it saves months of friction later. Third, embrace the ecosystem; the Java ecosystem is mature and battle-tested. Proven solutions such as Apache Tika, Jackson, and Spring Boot should not be reinvented. Fourth, understand memory and performance tuning; the JVM is powerful but requires thoughtfulness around garbage collection and heap settings. Spend time understanding these basics upfront. Finally, if you come from a Python and JavaScript background such as my team, budget extra time for the learning curve. Java has different paradigms and conventions, but it is worth learning because the payoff in stability and production reliability is genuine.

OpenJDK Java proved itself in a real mission-critical scenario for us. Financial document processing is not forgiving; if your parsing fails, your entire downstream pipeline breaks. The fact that we can rely on OpenJDK Java and Apache Tika to handle that responsibility consistently over 18 months speaks volumes. I would emphasize the longevity factor; OpenJDK Java is backed by the Java community and Oracle, providing confidence that this platform will be supported and maintained for years to come. That is important when building systems that clients depend on. Furthermore, if you evaluate solutions for backend infrastructure or document processing, do not overlook OpenJDK Java just because it has been around for decades. Its age is actually a strength, not a weakness, signifying that the platform has been battle-tested in countless production scenarios, where bugs have been found and fixed, and the best practices are well established. I provided an overall rating of 8 out of 10 for OpenJDK Java.

OpenJDK Java is one of the open-source Java development kits that I use. With all the Java libraries included in the JRE, I can handle all cases regarding object-oriented programming. However, it does not include J2EE (Java Enterprise Edition). OpenJDK Java is used for Java development and can be utilized in Spring Boot, Spring framework, and other play frameworks.

OpenJDK Java provides nearly all the functionality that Java uses. When comparing OpenJDK Java to Java EE, OpenJDK Java offers better code reusability through OOPs features, class collections, and collection frameworks. These features also bring some J2EE capabilities through beans. A main feature is that OpenJDK Java has Long-Term Support (LTS). For example, Java 21 has long-term support, and Java 1.8, Java 11, and Java 17 also have long-term support. Additionally, there is no cost for development, whereas Java EE is a paid feature where beans are handled by Java. From Spring Boot and Spring framework, I can use OpenJDK Java effectively.

OpenJDK Java runs on Windows, Linux, and macOS across every type of operating system. Similar to Java, OpenJDK Java compiles with Java code into bytecode, which runs in the JVM machine. All the features included in JEE are already present, such as Java compile code, Java run program, Javadoc, and job running and debugging. Multithreading is supported by OpenJDK Java. These are powerful tools, and high performance is available. JIT compilation and adaptive optimization are also present, along with regular updates as a main feature.

Java typically updates twice a year, with updates occurring every six months. Regular updates include bug fixes that do not impact the code if I use LTS (Long-Term Support). If a small update comes, that is fine. If a big update comes, I can also handle it. LTS support will always be available as a key feature. Currently, Java 21 has LTS support, and any update that comes will support my code.

OpenJDK Java can be used for Java development in Spring Boot, Spring framework, and other play frameworks. OpenJDK Java provides code reusability through OOPs features, class collections, and collection frameworks. Long-Term Support exists in OpenJDK Java for versions such as Java 21, Java 1.8, Java 11, and Java 17. OpenJDK Java runs on Windows, Linux, and macOS. It compiles with Java code and supports multithreading, high performance, JIT compilation, and regular updates.

Bean optimization could be improved. When comparing Java 1.8, which has a basic structure with for loops, to the stream API, the libraries are beneficial but slower. A for loop is a single loop that runs at the core level, whereas the stream API does the same thing but with slightly lower performance. Several improvements could be handled: performance improvement, better garbage collector latency, cloud container awareness, and cleaner syntax. Additionally, lambda is complex for beginners, so the usage of lambda could be improved.

The world is moving toward generative programming and AI usage with agentic approaches. Developers should have better handling of automatic GC performance issues. When compiling anything and an error is thrown, I want developers to have better performance insights into how this error will occur. Through AI, they can debug more effectively. Currently, when errors come, they are not straightforward. Developers have to read between the lines. If AI explains the error response, that would be better. Additionally, code usability could benefit from AI agentic capabilities.

I am currently using OpenJDK Java.

I do not think there are any stability issues. Java has a very large community, so if anything comes up, I am able to resolve it. In this AI era, most issues can already be resolved. I do not believe any challenges have come that cannot be overcome.

I do not think there is any scalability issue in OpenJDK Java.

I do not think there are any challenges with initial setup. However, when installing any application, everything should be set up automatically, similar to how Java is installed. There should be no need to write environment variables. They should already be set up in the system. At the beginner level, developers can only write the code and do not have to use environment variables at all.

The API impact on OpenJDK Java is minimal. When using the Spring Boot framework or similar frameworks, most things and beans are handled by the Spring framework. OpenJDK Java supports method level functionality with no difference from J2EE. However, bean handling can be a consideration because J2EE handles beans more efficiently compared to other frameworks. J2EE uses better bean optimization. Apart from this, I do not think there is any other issue. Most libraries already support both J2EE and OpenJDK Java, so I do not think there is any other impact.

Regarding development impact, performance-wise, OpenJDK Java is faster. One of the best features is that I can change my code and create my own compiler. Whatever method I choose, I can modify the code in JIT within OpenJDK Java. This is not possible in J2EE as J2EE does not allow these things. In Java 1.8, I can also change the background code and library code as this is allowed.

OpenJDK Java is open for everyone, every developer, and every company, and it is free of cost. There is no deployment cost or any such pricing. OpenJDK Java can be used for developing any type of software that uses API level functionality, such as backend software. I gave this review a rating of 8.5 out of 10. If a company is choosing Java tools, they should go for 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 the past eight to nine months primarily for developing and running enterprise and web-based applications. Most of my work involves building back-end services, automation scripts, and Java-based tools that integrate with Linux environments and containerized platforms.

Recently, the task where I used OpenJDK Java was deploying a Java-based web application on a Linux server using Apache Tomcat. OpenJDK Java served as the runtime environment, and I used it for application testing, configuration, and troubleshooting to ensure stable performance in production.

Besides running and supporting Java-based web applications, I also used OpenJDK Java for learning and testing new Java features, troubleshooting application issues, and working with containerized environments such as Docker and Kubernetes.

The best features of OpenJDK Java are its cross-platform compatibility, stability, strong performance, automatic memory management, and large ecosystem of libraries and frameworks. Being open-source and widely used in enterprise environments also makes it a reliable choice for development and production workloads.

The feature that I have found most valuable is stability and reliability because in my day-to-day work, it helps ensure that Java applications run consistently in development, testing, and production environments with minimal issues. This reduces troubleshooting time and gives me confidence when deploying applications on Linux servers and containerized platforms.

The feature worth mentioning is OpenJDK Java's strong ecosystem and community support because it is widely adopted. There is extensive documentation, a large collection of libraries and frameworks, and plenty of community resources available, which makes development, troubleshooting, and learning much easier.

OpenJDK Java has positively impacted my organization by providing a stable, reliable, and cost-effective platform for running Java applications. Its open-source nature eliminates licensing costs, while its strong performance and compatibility help ensure smooth application deployment and maintenance.

While I do not have exact figures, one noticeable benefit has been avoiding commercial Java licensing costs by using OpenJDK Java. This allows us to run and maintain Java-based applications without additional runtime licensing expenses while still receiving the performance and stability needed for production workloads. Additionally, its reliability helped reduce downtime and troubleshooting effort, improving overall operational efficiency.

OpenJDK Java could be improved by making version upgrades and long-term support management simpler, especially for organizations maintaining multiple Java applications across different environments. Improved built-in monitoring and diagnostics tools along with more streamlined performance tuning would also make troubleshooting and administration easier for developers and system administrators.

The documentation is generally good, but it could be improved with more beginner-friendly guides for upgrades, troubleshooting, and performance tuning. More practical examples for cloud and containerized deployments would also be helpful.

I have been using OpenJDK Java for more than eight to nine months.

OpenJDK Java is very stable. In my experience, it provides consistent performance for development and production workloads, receives regular updates, and is widely used in enterprise environments.

OpenJDK Java is highly scalable. It can support everything from small applications to large enterprise systems and cloud-native workloads. It works well with technologies such as Docker, Kubernetes, and distributed architectures, allowing applications to scale efficiently as demand grows.

OpenJDK Java itself does not provide dedicated commercial customer support because it is an open-source project. However, it has a large community, extensive documentation, and active forums. Organizations that require enterprise-grade support can obtain it through vendors such as Red Hat, Oracle, or Eclipse.

Setup is straightforward, especially on Linux systems, and the overall cost is mainly related to infrastructure and maintenance rather than software licensing.

No formal evaluation was conducted in my case. OpenJDK Java was already the standard Java runtime being used because of its open-source nature, reliability, broad industry adoption, and compatibility with enterprise applications.

While I do not have specific ROI metrics, I have seen value through avoiding commercial Java licensing costs, reducing software expenses, and leveraging a stable, widely supported platform. OpenJDK Java also helps save time by providing reliable performance and a large ecosystem of tools and documentation, which reduces troubleshooting and development effort.

Since OpenJDK Java is open source, there are no licensing fees for using the runtime, which helps reduce costs.

OpenJDK Java integrates very well with other technologies in my environment. It works seamlessly with databases through JDBC, supports REST APIs and web services, and fits well into DevOps workflows using tools such as Docker, Kubernetes, Git, and CI/CD pipelines. This compatibility makes it easy to build, deploy, and maintain enterprise applications.

OpenJDK Java updates and patch management are handled through my standard system maintenance process. The infrastructure team regularly applies security patches and version updates during scheduled maintenance windows, with testing performed before deployment to production to ensure application compatibility and stability.

The learning curve is generally moderate. New developers can learn the basics quickly, thanks to Java's clear syntax and extensive documentation, while more advanced topics such as enterprise frameworks, performance tuning, and large-scale application development take additional experience to master.

OpenJDK Java supports compliance efforts by providing a secure and well-maintained runtime environment with regular security updates and patches. While compliance depends mainly on application design and organizational processes, OpenJDK Java helps by offering a stable platform that aligns with enterprise security and governance requirements.

Personally, I expect OpenJDK Java to continue evolving with improvements in performance, security, and cloud-native development. I am particularly keeping an eye on enhancements for containers and Kubernetes environments, better support for modern application architectures, and continued innovation through regular Java releases while maintaining backward compatibility.

OpenJDK Java remains important for my future plans because many enterprise applications and backend services rely on Java. Given its stability, strong ecosystem, and open-source nature, I expect it to continue being used for new applications, modernized services, and cloud-native deployments in the future.

It is generally easy to find developers with OpenJDK Java skills because Java is one of the most widely used programming languages. There is a large talent pool, extensive learning resources, and many developers already have experience with Java-based applications and frameworks.

I would recommend OpenJDK Java to organizations looking for a reliable, mature, and cost-effective Java platform. It offers strong performance, broad ecosystem support, and no licensing costs. My advice would be to choose an appropriate LTS version, establish a regular patching process, and thoroughly test applications before major version upgrades to ensure compatibility. I have provided this review with an overall rating of nine out of ten.

On-premises

My main use case for OpenJDK Java is developing enterprise-level back-end applications. I used Java, particularly with Spring Boot frameworks, to build secure and high-performance REST APIs. Java is also my go-to language for integrating it with databases like Oracle and MySQL and handling message systems such as Kafka and RabbitMQ, as well as implementing validation frameworks.

In my recent role, I developed and maintained OpenJDK Java Spring Boot microservices for an enterprise compliance and sanctions platform using OpenJDK Java as the runtime environment for all our back-end services to ensure open-source compatibility and ease of deployment. My responsibilities included designing the REST APIs, implementing the business validation frameworks, and integrating with Oracle databases and Kafka systems. The application handled critical workflows like watchlist onboarding and attestation and required high reliability and scalability, which OpenJDK Java provided.

In addition to the back-end, I used OpenJDK Java for implementing automated testing frameworks such as JUnit and Selenium to ensure code quality and reliability. I appreciate OpenJDK Java's regular updates and security patches, which helped maintain compliance and stability in production environments.

Out of those features, I rely mostly on OpenJDK Java's strong support for multithreading and concurrency in my day-to-day work. I often build back-end microservices that need to handle multiple requests simultaneously and process large volumes of data efficiently. OpenJDK Java's concurrency features, like the executor framework and synchronized collections, help me design scalable and responsive applications.

Using OpenJDK Java has impacted my organization positively. It has significantly improved productivity by providing a stable and mature platform. The rich set of libraries and frameworks like Spring Boot and Hibernate accelerates development and reduces the time needed.

By leveraging these OpenJDK Java frameworks and libraries, we reduced our development time by approximately twenty-five percent, allowing us to deliver features faster, and the automated memory management and troubleshooting have contributed to a fifteen percent reduction in production incidents and downtime.

The best features OpenJDK Java offers include robust cross-platform compatibility allowing applications to run seamlessly on different operating systems, strong memory management and garbage collection. There are rich standard libraries and APIs for networking, excellent support for multithreading, regular updates and security patches, wide ecosystem support including frameworks like Spring Boot, and strong backward compatibility, making it easier to maintain, along with an active community and extensive documentation.

Its cross-platform compatibility has reduced infrastructure costs as applications can be deployed on various operating systems without major changes. OpenJDK Java's strong memory management and garbage collection have contributed to system reliability, minimizing downtime and performance issues.

OpenJDK Java can be improved in startup time and memory footprint, especially for microservices and cloud-native applications where lightweight containers are preferred. Enhancing native integration and support for modern deployment models like serverless and containerized environments would make OpenJDK Java even more competitive. Simplifying the module system and improving the documentation could help reduce the learning curve for new developers. Continued investment in performance optimizations, especially for garbage collection and low-latency applications, would benefit high-throughput systems. Expanding the ecosystem of tools for monitoring, profiling, and debugging OpenJDK Java applications in distributed environments would further support enterprise adoption.

Improving the onboarding experience for new developers by providing more interactive tutorials, better documentation, and enhancing IDE integration with more out-of-the-box tools for code analysis is necessary. Increasing the visibility and accessibility of community-driven resources would also be beneficial.

I have been using OpenJDK Java for seven years, starting from the early stages of my career. I have used various distributions of OpenJDK Java. In my recent years, it has become more of a standard in many of our enterprise environments.

I would advise others looking into using OpenJDK Java to take advantage of it and regularly update to the latest release, mainly to benefit from security patches. Also evaluate your application's compatibility with the specific version planned for use and leverage strong community support and extensive documentation available for troubleshooting and best practices. It is wise to integrate automated testing and CI/CD pipelines to ensure smooth deployments and maintain code quality.

OpenJDK Java has a very reliable and robust platform, and its open-source model encourages innovation and transparency. The flexibility to deploy OpenJDK Java across different environments, on-premise, cloud, or containers makes it a versatile choice. I would rate this product a ten out of ten.

Hybrid Cloud

Amazon Web Services (AWS)

OpenJDK Java is used centrally for developing back-end services like APIs, batch processing, and file processing. It is easy to integrate OpenJDK Java with any other product or other languages regarding cross-platform capabilities.

What stands out for me about OpenJDK Java is that it is good for processing fast and very efficient in memory management from a technical perspective. It is fast, reliable, and easy to develop any concept in the payment industry.

The community support in OpenJDK is very helpful for my development process. The community has helped me with information on the latest features they added, new encryption and decryption methods, and how the internal memory works. These are the pieces of information I can get from the community channels.

I see a benefit from the regular updates in OpenJDK, as it is beneficial when we face many challenges in development. The regular updates from Oracle provide patches to solve different challenges in terms of security and memory management. From a developer's point of view, it also makes tasks easier.

Regarding OpenJDK, I do see areas for improvement, though I cannot currently comment on potential improvements. I acknowledge that there is a chance for enhancement.

Comparing OpenJDK Java with Python and other scripting languages, I find it a bit bulky, as it takes a lot of effort to enable scripts in a system. While Python is good for small tasks and easy to deploy, OpenJDK Java requires more effort for similar tasks.

I stopped using it in March 2025, which is more than a year back now.

OpenJDK Java is 100% stable and demonstrates no downtime or glitches.

OpenJDK Java is scalable.

Community support is available, and there is also technical support with many discussions happening in different communities since it is an open platform, offering a lot of assistance. In my case, community support has been sufficient, and I did not need to reach out to technical support for the product.

Installation for OpenJDK Java is easy, with not much complexity in the steps.

I can observe savings in my ROI and categorize it as money-saving. If I quantify the savings, I see about 60% in money savings and 40% in time savings.

In terms of licensing and pricing for OpenJDK Java, I find it affordable and not expensive.

I have experience with TiDB Cloud as I have been using that product before. I am working right now with multiple vendors and not only with a particular database, as I am using front end and back end languages including React and Angular. I am currently writing some Python code and back end Java.

The languages I am using include Angular, React, Java, and Python. PowerCARD is the product I am currently working on, which is a card product and an HPS product.

I am using OpenJDK Java and confirm that I use OpenJDK Java. I have around 10 plus years of experience with OpenJDK Java. I work with the product not only as a user but also as a consultant, working as a consultant with the vendor.

APIs impact my development speed positively as it is fast and secure, and it is easy to integrate across platforms with different tools and technologies. Almost all the tools available in the market are Java JDK enabled, making integration with OpenJDK Java very easy.

The cloud-native capabilities in OpenJDK Java are beneficial for my projects, as about 80 to 90% of the projects I work on in the card and payment industry are running on OpenJDK Java. I work in a hybrid environment, using a mix of cloud and on-premises solutions.

I have solutions available on AWS Cloud, and OpenJDK Java is compatible with AWS and Azure, as I use both. As of now, I have not purchased anything from the AWS marketplace.

I give this review a rating of 8 out of 10.

Hybrid Cloud

Amazon Web Services (AWS)

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.

My main use case for OpenJDK Java is developing a telecom product which requires OpenJDK 21 with Apache Kafka. We are using Apache NiFi, and that was the major requirement for OpenJDK because we were using the Apache NiFi latest version which uses Java 17 and above versions.

A specific example of how OpenJDK Java fits into our telecom product is that Apache NiFi requires Java 17 and above versions, and OpenJDK is a free version which can be used. We use it and also use virtual threads for Java 21, so we benefit from the features of OpenJDK.

The best features OpenJDK Java offers are that it is open source and all the latest Java features can be used in OpenJDK. We used OpenJDK 21 version with those features, including virtual threads and strings which are also part of those features.

The most valuable open-source aspects and latest Java features for us are virtual threads which were the most frequently used in our application.

OpenJDK Java has improved our organization because it has some optimization techniques. Since our application was a high throughput application, we utilized these optimizations. We also make use of other Java features which are widely used in Java 17 as well.

OpenJDK Java already has so many features which are not part of other languages. As time evolves, OpenJDK is already getting enhanced with many features including Java Streams. We might need to include many libraries which are part of Python and are not currently part of OpenJDK. This would be a way to improve OpenJDK.

The needed improvements for OpenJDK include documentation and support which is already good from the OpenJDK side, and I do not find any problem currently. The OpenJDK community is not what we had earlier in the Java community, but it is acceptable. OpenJDK is already a part of our work.

I have been using OpenJDK Java for around 1.5 years.

I do not think we were using a different solution as we started using OpenJDK 21 when I joined this project within our organization which was a product development. The upper management was using this only.

I have seen a return on investment as I think a lot of money has been saved, but I do not have that number currently because higher management handles that in our organization.

My experience with pricing, setup cost, and licensing was good.

I do not have the answer to whether we evaluated other options before choosing OpenJDK Java because I have been part of a development team, and higher management only chose this. We made use of it.

The optimizations impacted our organization significantly since we were using Apache NiFi with OpenJDK 21, and our application throughput was really high. We were able to process 7,000 records per minute, so the throughput was really high and the performance was also good. The JVM was not running high and the performance was really good. I would rate this product a 9 overall.

Hybrid Cloud

Amazon Web Services (AWS)

My main use case for OpenJDK Java is any kind of application from server-side to JavaFX user interfaces to experiments with electronics on Raspberry Pi; there are many various ways of using OpenJDK Java.

A specific example of a project where I used OpenJDK Java is as one of the maintainers of the Pi4J project, which is a library that allows Java developers to interact with electronics connected to a Raspberry Pi. This is one of the main projects that I'm involved in as a pet project, where I also write all the documentation and the release notes for the Azul releases of the OpenJDK Java builds.

The best features OpenJDK Java offers are the ongoing evolutions and the many new features and improvements under the hood. Additionally, there is a very great community building amazing libraries that can do almost everything you can think of, and all these people are also very reachable at conferences and online, sharing a lot of great content. The tools are great, allowing you to build applications that are reliable, fast, and can be deployed on small servers or large instances. You can do desktop applications, and it's really the wide variety of things you can do with it.

OpenJDK Java has positively impacted my organization by allowing us to build whatever we want. There are either libraries available to create any kind of application, or it's very easy to add functionality to solve specific issues or even create a library that you can share with the community to help others.

Specific outcomes that show how OpenJDK Java has benefited my organization include that with Azul, we have a lot of data about that. For instance, if you are using Kafka running on the Java runtime and you switch to another distribution of the Java runtime, such as the Zing runtime, then you can achieve up to a 30% cost reduction because you need fewer servers or a smaller deployment environment to achieve the same load and reduce your costs.

OpenJDK Java could be improved in that there is a lot ongoing, and sometimes people complain that evolutions within Java are too slow. However, they are slow because they are really thought through, and any new feature that gets added to Java has been proven by the community to be the right way to solve a new way of thinking, methodology, or new functionality. It's designed to ensure Java stays backwards compatible while also making sure that new features can benefit from recently added elements. Thus, there is a lot of thought going into that. It could go faster, but on the other hand, I'm very happy with the stability that is consistent within OpenJDK Java.

I have been using OpenJDK Java for 20 years.

OpenJDK Java is definitely stable.

OpenJDK Java's scalability depends on your environment and your use case. That said, scalability is one of the main goals and achievements of Java, as it runs from very small instances to the largest possible deployments.

The customer support depends on which company you work with. For instance, Azul has really great customer support. I would rate the customer support a 10.

I did not previously use a different solution before OpenJDK Java.

I have seen a significant return on investment from using OpenJDK Java. There is definitely a big cost reduction if companies move from Oracle Java to either OpenJDK Java, which is totally free. You can get a lot of different distributions, and on the other hand, if you do need support, then Azul Zulu, for instance, as a core product, brings a lot of cost reduction compared to Oracle Java licensing.

I continuously compare all the OpenJDK Java distributions before choosing OpenJDK Java, and I'm very happy with the Azul Zulu one.

My advice for others looking into using OpenJDK Java is to look around at the community and check out foojay.io, the website for Friends of OpenJDK, where you will see that there is a lot going on in the community. The tooling gets new features, cleaned up, and improved, with articles about how to use OpenJDK Java or any other distribution. Just look around, as there is great content available if you want to get into Java. My overall rating for OpenJDK Java is 8.

Hybrid Cloud

Amazon Web Services (AWS)

OpenJDK Java is used for Spring Boot APIs written using versions 21 to 24. A specific example of how OpenJDK Java is used with those Spring Boot APIs is that it is built on top of OpenJDK, so it is used to compile and run the APIs.

The best feature OpenJDK Java offers is that it is free software with no licensing fees.

The free licensing aspect helps the organization by impacting the budget and helping save on costs.

OpenJDK Java has positively impacted the organization because, since Java was taken over by Oracle, it became very difficult to secure the license, which was heavy on the cost. OpenJDK Java helped to save on that, and it is very similar to the Oracle JDK.

Almost a million dollars in cost savings have been realized since switching to OpenJDK Java.

OpenJDK Java performs well overall. However, OpenJDK Java could be improved in terms of memory performance, and threads could be better optimized.

OpenJDK Java has been in use for 10 years.

OpenJDK Java is stable.

No scalability issues have been observed with OpenJDK Java; it scales very well.

The customer support for OpenJDK Java is very good with no problems.

Before using OpenJDK Java, Oracle Java was used, but the switch was necessary because of the licensing cost.

OpenJDK Java was purchased through the AWS Marketplace.

A return on investment has been realized, specifically in terms of money saved and time saved.

Approximately two hours daily have been saved in terms of maintenance since implementing OpenJDK Java, and in terms of project estimation, about four to six story points are saved.

The experience with pricing, setup cost, and licensing has been very positive; the licensing was free, and the cost was negligible.

Before choosing OpenJDK Java, Java was required, so OpenJDK Java was the only other option available.

OpenJDK Java is license-free for this use case.

OpenJDK Java is very performant, and memory issues are not commonly observed.

The advice to others looking into using OpenJDK Java is that if there is a need to save on the licensing cost and benefit from the advantages of Oracle Java, OpenJDK Java is recommended. This review has been rated 10 out of 10.

Hybrid Cloud

Amazon Web Services (AWS)