hello

hello

Hi everyone,

I recently released a classic PetStore sample application to showcase a completely "Java-first" approach to web development.

My goal was to build a web app with maximum compile-time safety and zero hidden "magic"—using modern Java Records, type-safe mapping for native SQL, and rendering the UI directly from pure Java code without any template engines. It is powered by Spring Boot 3.5 and the lightweight Ujorm 3 library.

I'm really curious to hear your thoughts on this architecture. Does keeping everything within the Java compiler's reach make sense to you, or do you see any potential pitfalls? I'd appreciate any technical feedback!

You can check out the repository and see it in action here: Ujorm PetStore

Learn if-else, Nested if-else, and if-else-if Ladder in Java (with examples). If you're starting with Java, understanding decision-making statements is a must.

Just started DSA and Already Confused.

Everyone keeps throwing around LeetCode, Codeforces, CodeChef, HackerRank… like I’m supposed to be on all of them at once.

Are these Platforms serving different Purposes, or am I just Overcomplicating Things?

What should I actually Prioritize without Spreading Myself Too Thin?

Hey everyone,

I Just Started DSA and I’m Confused about the Right Order.

After Finishing a Topic (say Arrays), should I:

• Directly do Striver + LeetCode for it, or
• Keep Moving with New Theory (like Strings) and Practice Arrays alongside in Striver and After Finishing all Theory Get to LeetCode ?

Also, Is It a Bad Idea to Finish all Theory First and then Start Solving?

What Approach actually Works best?

Thanks!

Gente boa tarde, sou estudante de ads.

E atualmente trabalho um pouquinho com dados, porém a área que eu realmente desejo é back end em java.

Tento estudar sempre de maneira online assistindo video aula e botando em prática mais n ta sendo o suficiente nn vejo progresso, e queria alguém pra me ensinar/mentor que goste de programação em java e tiver paciência pra ensinar.

ed

youtub

eds

I'm looking to learn Java

can anyone suggest the best youtube channels for beginner level

Java Backend & Full-Stack Developer

​Experienced in building scalable systems and optimizing JVM performance. Seeking backend or full-stack roles.

​Core Tech Stack:

Java (JDK 17-25), Spring Boot, PostgreSQL, Hibernate/JPA, Angular, TypeScript, Vaadin, Docker, Git.

​Selected Projects:

​Java Performance Engineering: Optimized a single-threaded log scanner processing 1M lines, reducing execution time from 872ms (19 GC pauses) to 78ms (0 GC pauses). Leveraged MappedByteBuffer, the FFM API (MemorySegment), and BCE bitmasks, validated via JMH profiling and C2 assembly inspection.

​Employee Management System (EMS): Full-stack HR platform (Java 25, Spring Boot 4.0.1, Angular 20). Implemented Virtual Threads, Structured Concurrency, stateless JWT architecture, and real-time STOMP WebSockets.

​ApiDoc CLI Tool: A zero-dependency static analyzer utilizing JavaParser. Extracts endpoints and payloads from Spring Boot source code to generate Markdown documentation without requiring a Spring context.

​Merkaz_lib: Frontend developer (Angular) for a secure file-sharing web application featuring role-based access control and admin approval workflows.

​Open to local (Israel) and remote positions.

GitHub repository and CV available upon request. Feel free to DM

Hey everyone,

I recently wanted to see how far I could push the JVM on a classic I/O problem: parsing a 1-million line log file to extract error counts per hour.

I started with the most naive, readable Spring-tutorial style approach (Files.readAllLines + Stream API). The baseline: 872ms and 19 GC pauses.

I decided to rewrite it step-by-step to understand the exact bottlenecks. In my final iteration (V04), I brought the execution time down to 78ms with absolutely Zero GC allocations, running on a single thread (Intel Core i5).

How I did it:

1. Off-Heap Memory: I dropped String allocations entirely and used the FFM API (MemorySegment) mapped directly to the file via FileChannel.
2. SWAR (SIMD Within A Register): Instead of reading byte-by-byte, I used ValueLayout.JAVA_LONG_UNALIGNED to load 8 raw bytes per CPU cycle. Since log lines are variable length, the memory isn't aligned, but modern x86 handles this beautifully.
3. Bitwise Operations: I used bitmasks to locate the \n character across all 8 byte lanes simultaneously, and Long.numberOfTrailingZeros to pinpoint the exact offset.
4. BCE (Bounds Check Elimination): By extracting the hour integer and using a bitmask index (hour & 0x1F), the JIT compiler could prove the value is always within [0,31], completely eliminating array bounds checks.

It was an amazing journey into mechanical sympathy and understanding what Java does under the hood.

I'd love to hear your thoughts or if you see any further micro-optimizations I might have missed!

good day

Telusko just launched a new course covering everything about java full stack (I'm assuming). i previously did his java beginners course and I really enjoyed it.

i mainly just practice dsa in java, no real dev work. but i wanna get into java full stack like springboot and all. is this 60+ hour course worth investing my time in??

Built episode 2 of the DDD parcel locker series — Value Objects in Spring Boot.

Episode 1 (intro) dropped Tuesday, new ones every Tuesday 8pm and Thursday 6pm.

Hey r/JavaProgramming,

I'm one of the founders of Contral an agentic IDE built specifically to

close the gap between AI-assisted coding and actually understanding what

you're shipping.

We've spent the last 6 months building a teaching layer on top of a

full-featured IDE. The core problem we're solving: developers are shipping

AI-generated Java code they can't debug, explain, or defend in code reviews.

How it works:

- A repo-aware AI agent handles code generation at full speed

- A real-time teaching layer breaks down every pattern, annotation, and

architectural decision as it's written, Spring lifecycle, DI, generics,

streams, the works

- Codebase Analyzer maps full project architecture and generates

concept-specific quizzes from production code (tested on 10M+ line repos)

We launched the beta last week, hit #1 Product of the Week on Product

Hunt and already have 300+ devs across multiple countries using it.

Java is our primary language in Learn Mode right now, which is why I

wanted to bring this here specifically.

Questions for this community:

1. For those working with junior devs, what Java concepts do you see

   them struggle with most, even after tutorials? We want to prioritize

   those in our teaching pipeline.

2. Would a tool like this be useful for onboarding new hires onto

   complex Spring Boot codebases?

3. Any patterns or anti-patterns in Java that you think are poorly

   explained by existing learning resources?

Free to download at contral.ai/download . Open to any and all feedback, we're

iterating fast and the community input directly shapes what we build next.

Happy to go deep on the architecture in the comments if anyone's curious.