I’m gearing up to publish my first Java library in the next few weeks. I’m using jspecify for null checking, with `NullMarked` annotations on my packages. Using my library requires implementing a subclass of an abstract class and overriding a method whose return value is marked as `NonNull`.

When I implement a subclass from my test suite, if I don’t have NullMarked enabled or if I don’t attach a `NonNull` annotation to the overridden method then I get a warning: `Not annotated method overrides method annotated with NullMarked`. So far so good; this seems like the tool doing its job by catching a potential source of errors.

Here’s my problem though: what if a consumer of my library doesn’t want to use jspecify? Am I dooming them to eternal build warnings? Is there a better way for me to have null checking in my library’s internal implementation and to publish it with useful `NonNull` annotations without locking consumers into a particular null checking dependency?

Life is full of setbacks. The only thing that matters is you keep pushing through them. It’s totally okay to feel frustrated along the way — but trust yourself, you can absolutely do it!

So I know the basics and OOPS concepts of java and I want to learn about spring, spring boot and microservices all the stuff which will make me industry ready. I have read a lot of reviews and it making me more confuse which to follow so what will be the best course for me also I do DSA with Java.

so last year. i decided i wanted to make apps. and decided to learn Java. i was 15 and stupid. so first thing i went through tutorial hell. i jumped from video to video. i also had no road plan. i just learn what was told on the videos. and i saw like ads about coding websites. and what matters with me is codedex. the first few levels were free. the rest were not. so i did the free ones then went to the projects and there i found out about swing. so yea. i was basically level one and was already learning swing. thats a dumb move. i kept my focus on swing and did some very simple apps. and then i realized that this was literally a waste of time. i knew basically nothing. but when i wanted to re learn it i felt myself skip skip skip because some things i knew. and lowkey giving up on Java.

I'm trying to understand how people structure a reasonably large Java/Spring modular monolith in practice.

I understand the general idea of package-by-feature / DDD / bounded contexts fairly well. For example:

orders/
submissions/
users/
catalog/

And inside a business module you can have things like:

api/
application/
domain/
infrastructure/

What I'm struggling with is everything that doesn't fit neatly into a business domain.

For example:

• security
• authentication / authorization
• CurrentUser / UserContext
• email notifications
• file storage / uploads
• PDF generation
• reporting Jackson
• configuration Web MVC
• configuration messaging
• observability
• global exception handling

Where do these things actually live in a real modular monolith?

For example, suppose I have:

submissions/
orders/
users/
notifications/
security/
config/
infrastructure/

A submission is created and I want to send a confirmation email.

Would you do something like:

submissions
|
| NotificationRequested
v
notifications
|
v
EmailSender

with notifications being an application module, and EmailSender / template rendering / SMTP being infrastructure?

Or would you put the email infrastructure outside the notifications module?

Similarly, where would you put CurrentUser? If every controller needs the authenticated user, should it be exposed by a security module? Does that mean all business modules depend on security?

And what about Spring Security annotations such as:

@PreAuthorize("hasRole('ADMIN')")

on controllers belonging to different modules?

I'm also wondering how this relates to Spring Modulith. I understand that it can enforce application module boundaries, but I'm not sure what the recommended approach is for these cross-cutting/technical concerns.

I'm specifically interested in real-world production codebases, not toy/tutorial examples.

How do you normally structure this in a large Java/Spring application?

If you have examples of mature open-source projects or architectural documentation that demonstrate this, I'd really appreciate them.

Hey everyone,

I’m a second-year transfer student at the University of Utah, and I’m feeling pretty overwhelmed about CS 2420.

My previous programming experience is mainly Python, and I’m now trying to learn Java. I understand basic programming concepts, but I’m finding the transition to Java harder than I expected.

I’m especially struggling with the basics and knowing what I actually need to learn before getting into the CS 2420 material. I've already asked my professor for help but he just said use chatgpt and google.

I’m also pretty stressed because I’m a transfer student and feel like I’m behind everyone else. I have some programming experience, but Java is making me feel like I’m starting over.

Hey all. I have a technical interview for an entry-level Java role coming up in about a week, and I want to use the time wisely.

Background: CS + Math degree, so I'm solid on data structures/algorithms and general logic, but almost all my hands-on coding has been in Python. I've been working through Java on Coursera and just finished the core OOP stuff (inheritance, polymorphism, abstract classes vs interfaces, exceptions, static/final). I'm comfortable with the syntax now but haven't done timed coding problems or "explain this concept out loud" style prep in Java specifically.

For people who've done entry-level Java interviews recently:

1. What actually got asked? Was it mostly OOP theory questions, LeetCode-style DSA in Java, or a mix?
2. Anything Java-specific that trips people coming from Python (I'm guessing things like static typing gotchas, collections framework quirks, == vs .equals())?
3. What would you drill hardest in a single week if you only had a few hours a day? Conceptual Q&A, coding problems, or both?

Not expecting senior-level stuff, want to walk in solid on fundamentals and not freeze up writing Java under pressure. Any resources, question banks, or "wish I'd known" tips appreciated!

So i wanna learn java as a hobby but what is the best way to learn it? Idk my goals yet maybe eventually mc mods but idk

And does is matter i dont know advanced math since i dropped school at 12 im 16 now and yes im working on jt

I completed my graduation in 2025 it's already a year wasted by self learning. l simply cannot learn on my own i just keep jumping from AWS to data analysis and now i want to take a paid coaching from a good coaching centre. It's for like 6-8 months of duration in java full stack by the time i complete the course it will be almost 2 years after graduation so a bit scared but want learn and get a job.Any suggestions that can help me guide and don't wanna lose my path to get a job.

Im planning to give this certificate exams cause I want to gain deeper knowledge in java and having an exam to focus on gives me a goal to achieve, so im more of a visual leaner and want to start with a pathway of videos and courses and then do practice exams, this is my strategy so far.

Im not that eager to read books or articles and prefer videos and practicing along.

I see oracle has a learning pathway that's build for java 21 programming and it has a pathway that looks good. So im trying to see if anyone has tried the pathway and found it useful for the cracking the certificate examination or are there any udemy courses that I could take that helps with my certification.

This is the pathway https://learn.oracle.com/ols/learning-path/become-a-java-se-21-developer/117252/138845

Also let me know any useful site that have a lot of practice questions to try

Hi everyone, I unfortunately was a person who used ai a lot in my intro to java class, would anyone have some resources or very good videos or even tutor sources online that could help out with me relearning some of the basics?

DO NOT USE AI, it blows..

Which language should i start DSA (product company)

- JAVA

- C++

- PYTHON

- OTHER

Guys help me,how I am able to learn java who don't know about coding at all , please give me legit answer and what are the steps I should follow after watching tutorial , please help me guys,want suggestions like if I watch one tutorial per day of any yt channel ,what should I do next after watching tutorial and in a month later

Any review about taking tesda course espicifically on Java programming course in C&C academy ?

Hi everyone,

I’m currently interning in a role that’s primarily DevOps and Support focused.

My daily routine involves:

Managing builds and pipelines in Jenkins.

Writing/enhancing pipeline scripts (mostly Groovy).

Linux server management and general troubleshooting.

While I enjoy the infrastructure side, my goal is to switch to a Software Development role. I’m planning to dive deep into Java and Spring Boot over the next few months to make the jump.

A few questions for the community:

Given my background in Jenkins/Groovy, what’s the best way to leverage that experience when applying for Java roles?

Are there specific Spring Boot modules I should prioritize to be "job-ready" for a junior dev position?

If you were in my shoes, would you focus on building a portfolio from scratch, or try to automate/build tools for my current internship to show "dev" impact?

I’d love to hear from anyone who has made a similar switch from Ops to Dev!

Hello,

I recently started with the Mooc Java course to refresh my knowledge a little bit and was wondering if anyone has made a PDF file with all the important notes from the course.

Would really appreciate if you could link it in the comments.

Hi, I would really love to learn java to do some basic modding, and following the advice of this subreddit I've downloaded the MOOC course and even looked at the help page to figure out why TMC Beans was initially not loading.

Well, now it is loading, but instead of opening the project exercises, it just goes deeper into the folders. So I'll click the Part 01 Sandbox assignment and instead of opening the Project, it just shows the src folder (and you can keep clicking within them).

Does anyone know any fixes for this? I've been trawling the internet and I cannot seem to figure it out.

Hi everyone,

I’m a Junior Flutter Developer with around 2 years of project experience, but I’m currently struggling to find a junior Flutter job, and I work in Egypt as German Speaker Customer Service Representitave with B1+ level

Because of that, I’m considering expanding my skills into Java + Spring Boot backend development instead of relying only on Flutter.

My plan is to learn:

Java → Spring Boot → REST APIs → PostgreSQL → JPA/Hibernate → Spring Security/JWT → Testing → Docker → Deployment

I’d really appreciate advice from people working in this field:

• What is the current future of Java/Spring Boot backend in Europe, especially Germany?
• Are there realistic junior/entry-level opportunities?
• How difficult is it to get the first backend job with no professional backend experience?
• Would combining Flutter + Spring Boot make my profile stronger?
• Is this a good career move in 2027/2028?
• Is there hiring and visa sponsorship for Juniors Spring Boot Backend

I’m not looking for generic advice — I’d really appreciate hearing from people who are actually working with Java/Spring Boot or hiring backend developers.

Thanks!

Heyy everyone, so I recently completed my Object Oriented Programming course and I solved problems using intellij java and scene builder for the UI. I also made a project but I'm looking for some ideas for projects that I can create using the concepts I learnt throughout this course. I really enjoyed learning everything so any suggestions are more than welcome. Also please suggest project ideas that'll be good for me when I apply for jobs in the future.

Thanks in advance!!

Looking for Spring Boot Resources

Hey everyone! I already know Java and use it regularly for DSA. Now I want to learn Spring Boot specifically for building real-world projects and becoming job-ready as a Java backend developer.

Are there any resources similar to the ones people recommend for learning Java/DSA Like MOOC.fi?

I'm looking for something that covers Spring Boot from the fundamentals to building production-level projects, including things like REST APIs, Spring Security, JPA/Hibernate, databases, JWT, microservices, etc.

I’d really appreciate recommendations for courses, YouTube channels, documentation, project-based tutorials, or roadmaps that you’ve personally found useful.

Thanks!

I’m a B.Tech 2025 graduate with internship experience and projects in the MERN stack.

Recently I have been seeing more job openings for Java, Spring Boot and microservices, so I’m thinking of learning Core Java, Spring Boot, Microservices while continuing DSA.

Should I focus on improving my MERN/Next.js skills, or start moving towards Java?

What would you recommend if you were in my position?

I am following a course on YouTube (62-hour video of Telusko) but all I am doing is watching and not getting any chance to practice what I have learned, fyi till now I have watched till interfaces (basically core java is just a little left).

I want code using concepts I have learned like some small projects.

Edit: Thanks for your suggestions everyone, I got it all figured out. I am moving forward with MOOC via vscode

I'm a Java learner and I've been learning Java for the past few months, but I still don't truly understand what an object actually is.

I've watched several YouTube videos and used AI tools to understand it, but I keep getting the same explanation: "An object is nothing but data + code."

I understand the definition, but I still can't visualize or feel what an object actually is when I'm writing Java code.

Could someone explain it in a simple, practical way, preferably with a real world analogy and a small Java example?

I feel like I'm missing one fundamental concept here. Any explanation would be really helpful. Thanks!

Basically I know tidbits about systolic array concept.

Every nxn square matrix does the same things during every tick of the clock.

1) Receive

it takes a number from the left and a number from the top.

2) calculate

it multiplies those two numbers together and adds them to whatever total it already has inside the box

3) Pass

left number is passed to the processor on its right. and the top number is passed to the processor below it.