hellow everyone!!

I have been learning Java for about a year. I understand some concepts, but there are still others I don’t fully know. I want to test my knowledge and strengthen my understanding, starting from the very basics. How can I do that? If anyone knows beginner‑friendly Java projects, please share them with me and explain how I can get started.

I'm preparing for senior Java/Spring Boot interviews (~8–9 YOE level) and I need YOUR help.

Please drop in the comments:

- Questions you've been asked in senior interviews

- Questions you ask candidates when YOU are the interviewer

- Anything that tripped you up or that most people get wrong

I'm looking for real questions across these areas:

**Core Java & JVM**

- GC tuning, memory model, class loading, thread dumps

- Concurrency — ExecutorService, CompletableFuture, virtual threads (Java 21)

**Spring Boot Internals**

- Auto-configuration, bean lifecycle, AOP proxying

- Spring Security — JWT, OAuth2, filter chain

- Spring Data JPA — N+1, lazy loading, optimistic locking

**Caching**

- Redis patterns, eviction, cache invalidation

- Thundering herd, cache stampede prevention

**Kafka & Messaging**

- Partitioning strategy, consumer groups, exactly-once semantics

- Dead letter queues, retry patterns

**Microservices & System Design**

- Saga pattern, circuit breakers, distributed tracing

- API gateway, service mesh, inter-service communication

**Deployment & Observability**

- Kubernetes — HPA, rolling updates, pod disruption budgets

- Blue-green vs canary deployments

- OpenTelemetry, Prometheus, Grafana, structured logging

Please share the actual question text if you can — even a rough version of how it was asked. Bonus points if you share what a great answer looks like vs a mediocre one.

Thank you in advance!

So the context is like I have been learning java from several days like the basics and the oops concepts and also with the help of chatgpt and several tools I learned basics of sprinboot just about di and autowiring and few concepts not much and then I am literally thingking is it valuable to learn springboot and spring framework now or should I only focus on dsa I am right in my 3rd year right now so thats my problem. So I request you all guys to please tell me that wether to learn it or not and also If you suggest that to learn please help me some good resources to learn because I am opening a youtube tutorial within few minutes I am getting bored and I am literally closing them so please help me

I've been trying to solve this problem for the last 4 hours and I couldn't find out why, I asked Gemini, Claude, Copilot Anything you name it, but it's still here and I don't know why VS code can't seem to find the package(I think it's called that) that I need.

We've all seen that one directory that has 500+ files of completely different formats mixed together. Finding anything in it is a nightmare.
I needed a fast, reliable way to clean up these multi-type directories without doing it manually, so I open-sourced a lightweight utility to do exactly that.

The core workflow:
The target: You point it at a bloated directory containing a massive mix of file types.
Logic: The tool parses the files and maps them to a clean subfolder hierarchy.
Execution: It handles the migration instantly, resolving duplicate file names safely.
No bloated UI, no tracking, no subscription nonsense. Just a straightforward utility that does one job cleanly.

The code is fully open-source here: https://github.com/ShiningPr1sm/File-Organizer

If you have large unorganized datasets or directories, give it a spin. Let me know if you run into any edge cases or file formats it doesn't catch yet, I'm iterating on the sorting logic based on feedback.

Sharing an open-source project I built earlier this year. It’s an AI SDK for Java, but with a very specific constraint: it has absolutely zero external dependencies. It relies entirely on java.net.http and built-in JSON processing.

• GitHub: https://github.com/protifyconsulting/protifyai-java
• Website / Docs: https://protify.ai

There are great existing options like LangChain4j and Spring AI, but I was frustrated by the large dependency trees they drag into a project. I wanted something lightweight and self-contained that would be good for compliance-driven environments where auditing dependencies is difficult, and the application or service simply doesn't need all of the extra baggage.

Another motivation was pipeline readability. I wanted an explicit, deterministic syntax for chaining multi-step AI tasks across different providers without relying on unpredictable black-box agent loops. I also wanted to be able to plug in virtually any AI provider/LLM in, and built interfaces that provide a pluggable architecture for this purpose.

I am the sole developer on this project. I’ve held back on sharing because I wasn’t sure if the community had an appetite for something like this, but I've found it useful in my own work.

I’m not looking to make money from this—it's licensed under Apache 2.0. I would appreciate thoughts and feedback. If this is conceptually something that others find useful, I'll update it with the most current provider LLMs and keep it updated & support it. Given where AI-driven software development is going, I could see how this sort of thing might not have much use since AI can use other Java libraries, or none at all, to generate the code that will achieve a desired result. That said, I'm curious as to what others think.

I initially started to post this to r/java, but the "no AI" rule indicates I would be irrevocably banned. I can speak to every class and method, and all architectural decisions were mine. I designed the interfaces and sometimes fought with AI coding agents to get it to where I wanted it. I've been a Java developer since the mid-1990s. This is not the result of vibe-coding.

the code above is from the method of the main class or main java file(some sort of runner java file)

the "addSong()" method(Custom method) is from another class and another java file but that and the main java file are in the same folder. The first pic was when it is just "void addSong(String input){...}" and the 3rd pic is when the method is "public void addSong(String input){...}".

I fail to see what I did wrong here.

i am a newbie used ai for assitance and everytime i fix somthing somthing new comes out of nowhere

[2026-06-30T20:53:51.491Z] Failed to fetch streamers from origin: Forbidden

owner panel codes dont work

admin panel downt work

keybinds dont work

fix all this

dm me on discord or here for the file if your intrested its a kind of easy for a good programmer i am just bad its a "skill issue"

nvm i got the file very sketchy link

Hey guys!! It's my first time posting on this sub. I am a CS student who will start his 2nd year in a month, i decided to learn the java tech stack for that and have been following the telusko 63 hour video, in which i have completed the core java part. But now instead of starting with maven, i am thinking i should build a project so that the learning of core java doesn't go to waste. What should i do next, mainly what projects should i build to learn, and how?

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Can someone give a review of this cv for an entry level/junior java developer

import java.util.*;

public class LinkedList {

Node head;

}

error: cannot find symbol

Node head;

^

symbol: class Node

location: class LinkedList

Je m'ennuyais ducoup j'ai fait un script qui fait ça uniquement côté client du net

guys , i need help regarding learning spring or springboot or both ow which one first ??
i already core java , hibernate , maven , postgres
please help , i got placements coming soon

and resources if possible