r/learnjava

i have 26 days till the ap csa exam (may 15th) and i know literally nothing (i thought i was going to be an academic weapon and self-study but that didn't happen bc im the biggest procrasinator ever). i have no computer science experience at all.

i want a 4–5 and i’m willing to study as much as needed each day, i just don’t know how to approach this without wasting time.

if you've taken csa before:

• how would u start if you were in my position?
• what topics matter most for the exam?
• what's the most effective way to learn this course?
• what resources do i use? (i thought of doing codehs but it's too long, i genuinly do not have enough time to get through all those lessons and practices)

any advice whatsoever would seriously be SO helpful. thank you!

I don't think I can ace my upcoming Java exams. I find it soo difficult. Methods,functions every single thing about it.

I spent almost 2 years pretty much learning everything needed to be a software dev. I switched from a non tech, non engineering domain.

My friend's uncle taught me everything from learning java core, spring boot, multi threading, to high demand industrial skills including kubernetes, Kafka, ci/cd, aws, distributed tracing, Microservices etc.

Even though I learned so much, it feels literally like a jack of all trades master of none.

Even if it's core java I have a hard time remembering the bean lifecycle and how wait, join, notify works in multi threading. I go back, review it, and it makes sense but I keep forgetting things time and again

What am I doing wrong? Why do I keep forgetting things? Anything that will help?

The title. I was doing performance tuning, and I somehow guessed that these spring provided rowmappers were a bottleneck. I removed that, and I have a custom rowmapper (basically, it caches the mapping from record's attributes to respective column in resultSet in a map-index, and searches by column index. Since my queries are static and map 1-1 to entity classes, this works very well). My solution was simple, but I'm trying to find exactly "why" spring provided rowmappers are way less optimized - is it due to some multi threading environment, or a lot of work which need not to be done? Also, why is searching by index way faster than searching by column name? I'm using Oracle. If anyone has any references, or any hints on how I could go forward in this knowledge hunt, I'll be grateful. Currently not getting anything relevant on Google search. ​

is it true that each thread has its own completely seperate classloader?

Hi everyone, I’m an immediate joiner having 3 YOE currently looking for java developer roles and going through so many thoughts and very confused about my interview prep at this stage. So, I thought of consulting a mentor on topmate I booked a session but the mentor didn’t appeared and also I can’t track my refund status so now having double thoughts on booking some other mentor. Also, there are so many newbie’s on the platform whose profile I can’t trust on. So, please help me out finding a good mentor who can give me some good suggestions as I’m not even able to study with this state of mind.

**I got tired of rebuilding auth from scratch on every Spring Boot project, so I made this**

Every new project, same story — JWT setup, OAuth2, email verification, password reset flows... it's tedious and eats up time before you even touch your actual business logic.

So I built a reusable authentication module you can just clone and drop into any Spring Boot project.

🔗 **[spring-auth-starter](Peter19570/Spring-Boot-Auth-Starter: A reusable Spring Boot authentication starter with JWT, OAuth2, email verification, and more. Clone, configure, and go.)**

---

**What's included:**

- JWT Authentication (access + refresh tokens, stored in DB, properly invalidated on logout)

- OAuth2 Social Login (Google, extensible to others)

- Email Verification on registration and password reset

- OTP-based flows for password reset and email change

- Rate Limiting on login and registration

- Audit Logging for critical actions (stored in DB)

- Soft Delete support

- Social Account Linking & Unlinking

- Async email sending (fast API responses)

- Flexible token handling — supports both HTTP-only cookies and Bearer tokens automatically

**Getting started is just:**

1. Clone the repo
2. Fill in your `application.properties` (DB, SMTP, JWT secret, OAuth2 credentials)
3. Run it

All auth logic lives in its own `authentication` folder — completely separate from your business logic. Just build around it.

Feedback, suggestions, and PRs are welcome 🙏

In almost every interview, I've been asked to write a code in java stream api.

With such questions, they are testing our memorization of stream functions, syntactical correctness and logic, which are not relevant.

How is this a measure of good java developer?

They should be checking whether candidate can write or design clean code, understand testing and jvm tuning, handling performance issues, these things are more relevant to day to day job.

Hey i am m 22 want to complete telusko java spring boot etc 62 hour course

Looking for study buddy with whom I can complete

For better consistency and help each other

Dm me

Java Developer (Fresher) – Interview Preparation & Guidance Needed

Hi everyone,

I’m looking for guidance on preparing for Java Developer interviews as a fresher.

I previously worked with the MERN stack and even secured a placement based on that. Recently, I completed training at Capgemini where I learned Java, including Spring Boot and related technologies. Now, I want to switch my focus from MERN to Java and update my LinkedIn profile and resume accordingly.

Before doing that, I have a few concerns:

• What topics should I focus on for Java Developer interviews as a fresher?
• What kind of interview questions are typically asked?
• What skills or areas should I strengthen to make this transition smoother?

I’m just starting out in Java development, so I feel a bit confused about the right direction and preparation strategy.

Any advice, resources, or guidance would be really helpful.

Thanks in advance!

Hey.. recently I developed a project for my clg internals. I used MySQL jdbc jsp servlet etc.. these are advanced java concepts right. I developed with the help of AI in eclipse which helped me like a partner. While developing this I came up with a doubt " do people who are developing websites and apps also use AI or they go up with frameworks for codes? " . Did I developed my project in the wrong way.?

Anyone clear my doubt by answering this..

Im trying to get into Java + SpringBoot, but im doing everything as a self taught. I have a degree but not a STEM one, i gratuated in Social Comunication, and i dont know if that will be a drawback for me getting a job in this.

Im not doing too well currently, and i want to try something new, but im cant afford getting into paid studies again, and i feel time is moving on ( im 30) So i want to try and get myself in as a self taught, but i dont know if all this will be worthy at the end, or im going to waste my time just because i dont have a tech background and gets rejected for a job because of it.

Also im from South America, my final goal is to get a remote job as Java/SpringBoot developer.

Hi.

I'm learning about Hexagonal Architecture and have some questions about where the in-ports (use case interfaces) and out-ports (repository interfaces) should be placed.

I've read various blogs, articles, and discussions where some people mentioned that ports must be located in the application layer, and others said they must be in the domain layer. I'm confused about the right place to put them.

I'd like to know your opinions and suggestions, please.

Approach 1 - Ports inside application layer

application/
- in/ (use case interfaces)
  - CreateProductUseCase     
- out/ (repository interfaces)
  - ProductRepository
- usecase/
  - ProductUseCaseImpl

domain/
- model
 - Product (plain object)

Approach 2 - Ports inside domain layer
domain/
- in/ (use case interfaces)
  - CreateProductUseCase     
- out/ (repository interfaces)
  - ProductRepository
- model
 - Product (plain object)

application/
- usecase/
  - ProductUseCaseImpl

Hey! I’m a 2025 graduate preparing for placements and currently focusing on Java + DSA. Looking for a serious and consistent study partner to practice daily, solve problems, and stay accountable.

If you’re also preparing and want to stay consistent, let’s connect 🙌 ASAP

i recently completed java deeply and also made handwritten notes now I am confused either I should do spring framework or start javascript (I have know html,css)

I want to become a java backend developer

or should I focus on dsa??? ....

Hey I just finished BroCode’s 12 hour java course but I don’t know what to do now, I feel like I haven’t learnt much from the course though. So what should I start with now ? proceed with advance java ? or start dsa or make small projects, help me out

Hello. I wanted to try and implement uncle Bob's Clean Architecture in SpringBoot.

Here's the github repo.

I need some feedback about it. Thanks again

I'm a btech 1st year student thinking of starting to learn java as my first coding language because still now I'm in 0 level of coding knowledge. But in this semester I have oops . Is it fine to learn java over c or python? or do I need to do something else?

I've been learning java for almost 8 months now and I am still feeling i haven't learn much about it, im thinking of improving my skills more but don't know where to start

Where can I learn Java for free? Something like FreeCodeCamp or The Odin Project, but for Java. I've found some, like Hyperskill, but it's freemium and others aren't in depth enough for actual serious learning (considering a career in Java, possibly).