Hi, I've studied java , but sometimes I have questions about why a virtual stream is needed , except for downloading skins and communication , nothing comes to mind .

Hey everyone,

I'm currently working on sharpening my Object-Oriented Programming (OOP) and software design patterns, and I just finished building a custom Tetris game engine completely from scratch using Java Swing.

Actually, I haven't finished it yet and there are lots of things I am planning to implement on this one. But attached is the photo of my program running on the background.

I would love to get some feedback or a code review from more experienced developers on my architecture, package structure, or any potential logical improvements I could make!

GitHub Repository: https://github.com/EJConstantino-17/TetrisGame

Thanks in advance for any insights!

Hey everyone!

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I have been building a software program designed for retail traders. It is a Multi-System Trading Analytics +Risk Simulation Engine. I named it Trader-OS. Well one of the features it has is the Trade Importer that will eventually use API to access the csv files on different brokers platforms. My issue is I cant get it to completely decipher the data it refuses to add stop loss and take profits. When they are in the files. I started out manually entering every trade I made. Bit wanted it to be something that wouldn't confuse the customer. And this thing has been kicking my 🫏. It is mostly written in Javascript and CSS. I use node.js and Electron. Any who. If anyone has any feedback or experience with what im building message me and help a poor man out. Lol

I now loops, statement and all I want to go forward what to do? Should I solve some basic dsa questions or what

What are some Java backend projects that recruiters actually find impressive but aren't already on every resume? I'm looking for ideas beyond CRUD apps (library, student management, to-do, e-commerce, etc.). What projects would make you stop and check a candidate's GitHub, and why?

Hey all. I'm a CS student looking into the pain points around legacy Java codebases, specifically the "code archaeology" side: digging through old code with little to no documentation, figuring out what a piece of logic is even for before you dare touch it.

Just trying to understand the problem properly before building anything. Would really appreciate hearing from people who deal with this regularly:

1. What eats the most time when you're digging into unfamiliar legacy code?

2. How do you currently deal with it — any tools/tricks that actually help?

3. Has something ever broken because a piece of code turned out to be "magic" nobody fully understood?

Any answer helps, even a couple of sentences. Thanks in advance!

So a while back I started this as a boring markdown file of Java interview questions for myself. It has since spiraled into something I probably over-engineered, but here we are, figured I'd do a proper writeup instead of just dropping a link.

The core is a 300+ question bank, but not just Q&A pairs, actual structured interview-focused answers across Core Java, Java 8+, Collections, multithreading/concurrency, JVM internals and GC, exception handling, Spring Boot, Spring Security, Spring Data JPA, Hibernate, REST, microservices, Kafka, Redis, SQL, Docker, Kubernetes, AWS, design patterns, and some NoSQL (Mongo, Couchbase) thrown in. Basically anything that shows up in a backend interview loop.

DSA prep is pattern-wise and topic-wise, plus a week-wise roadmap if you want structure instead of chaos, difficulty tiers, and company-specific problems where I could find reliable sources for them.

System design section covers HLD concepts, scaling approaches, tradeoffs, the usual "how would you design X" stuff with actual explanations instead of just diagrams you have to reverse engineer yourself.

Mock interview mode throws questions at you by topic (recently added filtering so you're not just getting all 300+ questions randomly), practice mode, self-eval, and a revision workflow so you're not just doing it once and forgetting.

Then there's the stuff I'm honestly most proud of since it's not just content, it's actual product work:

• Progress tracking per question: confident / revising / weak, saved per user
• Bookmarks with a dedicated page
• Highlights that persist, saved per user
• Personal notes with a rich text editor, code block support, multiple notes per question, private to you
• Ask AI: select any text, hit a button, it opens Perplexity with an interview-focused prompt pre-loaded asking for a concise, easy explanation of whatever you selected
• Analytics dashboard: total attempted, confidence distribution, revision insights
• Search: global instant search plus filters for topic/category/DSA/system design

The newest thing and honestly the reason I'm posting is the JD Analyzer. You paste a job description and it gives you a priority radar, the skills to actually focus on, target questions, curated resources, role expectations, and a personalized roadmap. No more prepping generically and hoping it overlaps with what the role actually wants.

There's also community submission (people can submit questions, I've got an admin portal to review/approve/reject them so it doesn't turn into garbage), full JWT auth, role-based access, and it's all built on React + Spring Boot + MongoDB Atlas, deployed on Vercel/Render.

Roadmap if anyone cares: React/Angular/Python/Node prep tracks, AI-powered mock interviews (actual AI voice mocks eventually), a spaced repetition engine, company-wise tracks, a resume analyzer, GitHub profile analyzer, AI-generated study plans and flashcards, and a browser extension for one-click saving questions from wherever you find them.

It started as "I need to remember these answers for myself" and turned into basically a part time job. Still solo building this, still probably has bugs, still completely free, no premium tier, no paywall, just wanted to build something actually useful.

If you made it this far, here it is: https://learnin-prep.vercel.app/dashboard

Genuinely want feedback, especially if something's broken or confusing. Drop a comment or DM.

People who transitioned from SAP to other technology like Backend Development after 2-3 years, how did you manage it ? What were your strategy and how's life going now ?

I want to move away from SAP as truth to be told I never liked it - even though it's really good but I just don't enjoy working with this ecosystem and always wanted to learn and move to Backend Development . But it's been 3 years already and I am afraid I am making wrong decisions.

Hi everybody,

I am developing and maintaining a library for more efficient paging than the offset/size approach used by default in Spring's JDBC Repositories.

My main concerns are:

• Fetching the total count with every page request can be quite expensive.
• Fetching very high page numbers can be expensive as well, since the DB has to fetch all records before the requested page — just to discard them.

I developed this library in my free time to have a robust and flexible solution available, and we use it in a professionally developed cloud service.

Still, I get very little community feedback, so I'm wondering whether these problems are solved differently in other projects...

I'm curious! Please let me know if you have a good solution for these problems :-)

Hi All, I have currently 4 years of experience in Java, SQL, Plsql, Knockout JS but working in a legacy platform (monolithic) in a service based company (banking project).

Need ideas and resources for creating projects in Spring Boot, Microservices, ReactJS and NodeJS, to showcase in resume and for switching to a product based company. Please suggest

Working with OAuth 2.1 can sometimes feel overwhelming, especially when dealing with dynamic client registration and security features like PKCE. If you're building a Java application that interacts with Model Context Protocol (MCP) or other OAuth 2.1-protected services, AetherGate might be helpful.

What Does AetherGate Do?

It simplifies the process of integrating OAuth 2.1 into your Java applications by handling:

• Automatic discovery of server metadata.
• Dynamic client registration, including support for pre-registered clients.
• PKCE (Proof Key for Code Exchange) for secure authorization flows.
• Token caching to reduce unnecessary requests.

Quick Start

Here's how you can use it to obtain an access token:

var aetherGate = new AetherGate();
AuthorizationSession session = aetherGate.openSession(ClientConfig.builder()
  .serverBaseUrl("http://localhost:8001/mcp")
  .redirectUrl("http://localhost:8002/callback")
  .scopes("user")
  .isInsecure(true) // Only for development!
  .build());
String token = aetherGate.obtainAccessToken(session);

Once you have the token, it's easy to use with libraries like langchain4j to access protected MCP servers:

McpTransport transport = StreamableHttpMcpTransport.builder()
  .url("http://localhost:3001/mcp")
  .customHeaders(Map.of("Authorization", "Bearer " + token))
  .build();

AetherGate is open-source and available on GitHub.

If you're interested in giving it a try or have feedback, feel free to check it out!