Hi everyone,

I’d like to introduce a new Java desktop toolkit, built from the ground up.

It includes dozens of components, accessibility support across three operating systems (Windows, macOS, and Linux), advanced language support, text direction, video, music, 3D, and charts.

The appearance is fully customizable (including dark themes), animations are native, and all the features you’d expect are there: printing, desktop integration, and testability.

I hope the community enjoys it. Although it is—admittedly—the product of AI, it was crafted with great care over the course of several months, ultimately saving tokens for anyone looking to build desktop applications.

https://limn-toolkit.github.io/limn-toolkit/

Enjoy

Tengo un proyecto app web jsf , jakarta +open liberty etc

Me pregunto si me podrían ayudar dándome opiniones sobre el

What Java topics should every fresher prepare before attending their first technical interview?

I'm preparing for Java developer interviews and want to focus on the topics that matter most.

Vaadin's free agentic development tools give AI coding agents like Claude Code, Codex, Cursor and Copilot what they need to build Java web apps correctly

Hi guys, I compiled material that I’m used to conduct technical interviews into one material.
It’s covering Java Core and Spring Boot, so it’s not fully about Java.
All the code is tricky and hide a lot of different problems, this kind of brain teasers helping to start conversation about code and learn more about candidate experience. You can read only code snippets and figure out on your own or read instructions below.
I hope this material will be useful for someone.

I've been experimenting with optimizing a conventional Spring Boot application on HotSpot JDK 27, without switching to GraalVM Native Image.

The setup was a 512 MiB / 1 vCPU Ubuntu VM with no swap, running Spring Boot 4.1.1 and MariaDB on the same machine.

I compared a regular executable JAR with an extracted deployment using Spring AOT and a trained JDK AOT cache (Leyden).

Results:

• Startup: 11.91s → 3.79s (68% reduction)
• Median app RSS: 212 → 187 MiB
• Minimum host MemAvailable: 25.6 → 66 MiB
• Request latency: essentially unchanged

One interesting issue: the JVM initially rejected the trained cache because transferring JARs changed their timestamps. The application still started normally, so I had to verify cache acceptance through JVM logs.

I also tried replacing Spring JDBC with manually integrated MyBatis Core. It didn't produce meaningful memory savings and required additional transaction management.

These are single-run observations at 5 rps, with the optimizations combined rather than isolated.

Full write-up and measurements:
https://pvrlabs.xyz/articles/spring-boot-jdk27-optimizations.html?s=rjp

Has anyone experimented with JDK AOT cache in actual deployments? I'm curious how you manage cache training and validation as part of your build pipeline.

Hi everyone!

I have an upcoming Build It coding interview for a Graduate Software Engineer (Java) role at Revolut, and I’d love to hear from anyone who has gone through this round recently.

I’ve read a few posts about the Build It interview, mentioning practical coding exercises where requirements evolve during the interview, followed by discussions about concurrency, database design, SQL, and performance.

I’m trying to get a better understanding of what to expect at the graduate level, so I’d really appreciate any insights!

• What kind of problems were you asked to build?
• How much emphasis was placed on Java fundamentals, data structures, and algorithms versus practical software engineering?
• Were you asked about multithreading, concurrency, or database locking?
• Were you expected to write unit tests during the exercise?
• Were AI coding assistants allowed, or was it strictly manual coding?
• What would you recommend focusing on when preparing for this round?

I know the experience may vary between teams and locations, but I’d especially appreciate feedback from people who interviewed for a Graduate Software Engineer role using Java.

Thanks in advance for sharing your experiences!

I conducted a mock interview recently and one thing stood out to me.

I asked a Java question related to concurrency:

class Counter {
    private int count = 0;

    public void increment() {
        count++;
    }
}

“Is this thread-safe?”

The candidate said "No".

So I asked, “Why?”

He knew that it wasn't thread-safe, but explaining exactly why was difficult. He then said we need to synchronise the method.

So I asked:

“How does that fix it?” and then “What exactly is being locked here?”

That was where the interview got interesting.

He knew the terms — synchronised, volatile, race condition, etc. However, connecting them and explaining what was actually happening between the threads was harder.

It made me think about how easy it is to prepare for interviews by remembering rules.

count++ → not thread-safe → use synchronised

But the moment someone asks “Why?”, we need to understand what is actually happening.

I think that's something that's easy to miss while preparing for interviews. We can keep solving questions and memorising concepts, but it's worth stopping sometimes and asking ourselves:

“Can I actually explain why this works?” and “What happens if I change one thing?”

How do you guys prepare for the “Why?” part of interviews?

Please don't expect much of it. It’s a Maven dependency, not a shiny click and play editor. There is no GUI interface. I built only the engine under the hood (rendering pipeline, light management, scene and asset handling, physics integration with Jolt), so you just drop the dependency into your project and write your scenes and logic purely in Java, like it should be, while Lumvex handles the heavy lifting.

Under the hood, it runs on JDK 21, Vulkan 1.3 and shaderc for runtime GLSL compilation. And yes, it currently has plenty of rendering bugs.

What I’m looking for (AMD Testing & Code Review):

Since the engine relies on Vulkan 1.3 hardware ray tracing and I only have an NVIDIA card to test on, I have no clue if the pipeline works properly on AMD GPUs. If anyone with an AMD GPU and JDK 21 could build it and let me know if any scene runs (or share the crash log), that would help me out a lot.

Also, if people who actually know Java want to take a look at the repo, feel free. Just don't hate on my code simply because you found a flaw. Point out actual ways to improve it instead (though I know most people on the internet are incapable of doing that).

About AI (yes, what a shock):

Yes, AI was used. No, it didn't write a single line of logic or the Vulkan/rendering pipeline. I used it to translate and clean up my half-German documentation and comments (you can tell at first glance which comments were written by me and which ones were created by AI).

https://github.com/LumvexJava/Lumvex

Edit: Linux support is planned, but currently in the VulkanCanvas (https://github.com/LumvexJava/Lumvex/blob/main/src/main/java/dev/lumvex/vk/VulkanCanvas.java), I hardcodet the VK_KHR_WIN32_SURFACE_EXTENSION_NAME and vkCreateWin32SurfaceKHR (Line 50 and 83), you will hit an UnsatisfiedLinkError or VkResult -7 if you try running it natively on Linux.

Edit 2: Found the Bugs! X11 (Linux/Nvidia) support is already working on my machine and will be included in the upcoming update :)

so basically a few nights ago i decided it was long time to update java and it kept saying something like “the files needed to run the installation couldn’t load” or something like that so i give up fast foreward to today i get the notification im like fuck it ill try to update it again and THIS time its saying “you have an unfinished installation”, but a few nights ago it told me it couldnt start. help?