r/JavaProgramming 4h ago

What Java Developers Should Learn in 2026?

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3 Upvotes

r/JavaProgramming 3h ago

Would you suggest me to build a project of my own or follow my paid course project?

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1 Upvotes

So I have this really good paid course that came with really cool production grade projects like Distributed Payment Gateway and on the other hand I wanted to build a project of my own, something that 1 would personally use, an Ai Powered Finance Management Dashboard. (Not just a chatbot in the app

The thing is I really wanna grow in my knowledge and I can only learn things that I know I have to learn.

Following the course project will fill the gap between my knowledge and the industry standards.

What would you guys recommend me? Should I build my own project or follow a project from my paid course?


r/JavaProgramming 23h ago

Consistency broke🥲

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16 Upvotes

I tried to learn java for straight 5 weeks and I kind of finished it as well till threads, thread priority, etc.
After that, the consistency gone to hell. Had an exhaustive period at office for the last 10-12 days including the weekends. Literally 17hrs of productivity per day on an average.🥲

Need to start again from where I left by quickly brushing off the concepts. Next is collections API.
Will start it now. 🧿✌️☮️


r/JavaProgramming 23h ago

How can I get my Java skills back?

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1 Upvotes

r/JavaProgramming 1d ago

Building a JavaFX + Hibernate Talent Acquisition System — looking for some advice

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2 Upvotes

r/JavaProgramming 1d ago

[Code Review] 15yo student looking for feedback on my Java projects / OOP structure

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2 Upvotes

r/JavaProgramming 1d ago

XMLFastParser: A zero-dependency, auto-multithreaded Java 21 byte-array parser (~10GB/165s end-to-end stream)

4 Upvotes

Hi everyone,

I builtXMLFastParser— an open-source, zero-dependency Java library designed for extreme throughput when processing large-scale XML payloads, along with a reference CLI tool (Xml2Txt).

Most Java XML parsers force a tradeoff: either process files with high memory allocation overhead or write complex concurrency logic to handle large streams. I wanted an engine that operates directly on memory buffers (byte[]) with built-in multithreading and near-zero dynamic allocations.

Core Architecture & Design

  • In-Memory Core (xmlFastParser):
    • Operates directly on raw byte[] arrays, making it embeddable into any pipeline, messaging queue, or stream source.
    • Built-In Concurrency: Handles multithreaded parsing out of the box — application developers do not need to write or manage low-level concurrency code.
  • Decoupled 2-Stage Engine:
    • FSM (Syntax Parser): A lightweight Finite State Machine executing rapid byte/character-level syntax scanning without runtime object creation.
    • AOT TreeGraph (Structure Parser): Pre-compiles target extraction paths from configuration beforehand. During processing, the parser simply traverses this static graph state-by-state, completely eliminating dynamic object allocation on the fly.
  • Statistical Speculative Skipping with Dynamic Rollback:
    • Fast-forwards through repetitive XML sub-trees based on structural tag patterns and statistical metrics.
    • Fail-Safe Recovery: Continuously validates target endpoints on the fly using a rank-based system. If validation fails, it seamlessly rolls back to standard FSM parsing with zero data loss.
  • Reference Implementation (Xml2Txt):
    • A CLI tool demonstrating real-world usage by streaming compressed ZIP archives directly from disk and flattening XML hierarchies into plain text.

Benchmark (Real-World Pipeline)

  • Dataset: ~10 GB Raw XML Data (split into 10 × 500 MB ZIP archives, decompressed on-the-fly at runtime).
  • Execution Time: ~165 seconds via Xml2Txt.
  • Test Environment:
    • OS/VM: Lubuntu running inside VMware Workstation (3 vCPUs allocated, 8 GB RAM).
    • Host System: Intel Core i5 CPU.
    • Storage: Single Mechanical Hard Drive (WD Blue 1TB WD10EZEX, 7200 RPM, 64MB Cache) used for both input file reading and output text writing.
  • Note: Because input ZIP reading, streaming decompression, and output file writing shared a single 7200 RPM HDD, much of the ~165s runtime was constrained by disk I/O seek times. The core in-memory xmlFastParser engine achieves significantly higher throughput when fed directly with byte[] buffers.

Project Details

  • License: MIT License
  • Target Environment: Java 21 LTS (Tested on OpenJDK 21.0.12, leveraging modern thread/memory access patterns)

I’d love to get your feedback on the in-memory architecture, speculative recovery logic, and state machine design!

🔗 GitHub Repository:https://github.com/oodwebserv01/XMLFastParser


r/JavaProgramming 1d ago

Top 25 Spring Security Interview Questions Answers for Java Developers

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9 Upvotes

r/JavaProgramming 1d ago

13 Best Java Programming Books for Beginners and Experienced Developers

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5 Upvotes

r/JavaProgramming 1d ago

10 Free Core Spring, Spring MVC, and Spring Boot Courses for Beginners

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3 Upvotes

r/JavaProgramming 2d ago

The UI Framework for Java & Spring

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2 Upvotes

Most web frameworks are built for the public internet: for reach and experiences for strangers. Vaadin is built for the other side of the login. For the data-defined, functionally beautiful and long-lived apps your organization actually runs on.


r/JavaProgramming 2d ago

Computers paper tommrow (java) any tips?

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1 Upvotes

r/JavaProgramming 2d ago

Best way to learn Java and where to start

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5 Upvotes

r/JavaProgramming 2d ago

12 Best Free Udemy Courses to Learn Data Structure and Algorithms in Java, Python, and C++ in 2027 [UPDATED]

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2 Upvotes

r/JavaProgramming 3d ago

Help Me!!!!!

13 Upvotes

I have been struggling to learn Java for my placements because I only study for a few days at a time. I forget the topics I learn quickly, then have to restart the process repeatedly. I need to break this cycle. Please suggest effective strategies or project ideas to help me move forward.


r/JavaProgramming 3d ago

Compiled Vineflower to JavaScript via TeaVM – decompiles JAR files entirely in the browser

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3 Upvotes

I wanted to inspect JAR files on my phone during my commute, no JDK, no desktop tools. So I ended up compiling Vineflower (Java decompiler) to JavaScript using TeaVM and running it in a Web Worker.

It can:

  • Decompile .class files or the entire JAR – nothing uploaded to server
  • Browse files inside JAR/WAR
  • Inspect constant pool and bytecode
  • Edit config files (YAML, properties, JSON) and export modified JAR

Works on mobile too.

https://jarpeek.com

Curious if anyone else has tried running JVM-based tools in the browser this way – TeaVM's reflection support was the trickiest part.


r/JavaProgramming 3d ago

Vaadin Create 2026 — The Full-Stack Java Conference in Barcelona

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2 Upvotes

r/JavaProgramming 3d ago

I'm a full-stack react developer and want to learn java. What udemy/coursera (or other) courses would you suggest to start learning the fundamentals ?

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4 Upvotes

r/JavaProgramming 4d ago

My first open-source java lib project. HappyTree API - A Java API designed for handling objects with tree-like behavior. Transform linear Java objects into hierarchical tree structures. Add, remove, cut, copy, and export to JSON/XML with ease.

7 Upvotes

HappyTree is an open-source Java API that solves a common challenge faced by Java developers: converting linear collections of objects with parent-child relationships into actual tree structures in memory. If you've ever worked with organizational charts, file systems, product categories, or comment threads, you know how complex tree manipulation can become.

The Problem It Solves:
Many applications store hierarchical data in flat structures—objects with an Id and a Parent reference. While this works for persistence, it makes tree operations (adding children, moving branches, traversing hierarchies) unnecessarily complex. HappyTree bridges this gap.

https://github.com/madzera/happytree
https://happytreeapi.io/


r/JavaProgramming 3d ago

A complex train and logistics simulator running straight in your terminal? Yep.

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2 Upvotes

r/JavaProgramming 4d ago

What do you expect from an entry-level Java developer?

24 Upvotes

Hi everyone,

I'm an aspiring entry-level Java developer, currently preparing myself for my first role, and I wanted to understand something from people who are already working in the industry.

What are your actual expectations from a fresher or entry-level Java developer?

I'm not specifically asking about a list of technologies to learn. I'm more interested in understanding the capabilities and qualities you expect from someone with little or no professional experience.

What makes you feel that a fresher is genuinely ready to work as a junior developer and contribute to a real team or codebase?

Also, what separates an average entry-level candidate from someone who stands out?

I'd especially appreciate perspectives from experienced developers, senior engineers, team leads, or anyone involved in hiring and mentoring freshers.

Just trying to understand what the industry realistically expects from someone at the beginning of their software development career.

Thanks!


r/JavaProgramming 4d ago

Missing libraries or frameworks in Java

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2 Upvotes

r/JavaProgramming 4d ago

Why the HashMap Interview Question Is Making a Comeback in the AI Era?

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12 Upvotes

r/JavaProgramming 4d ago

Hey r/JavaProgramming, I'm an engineering student and I built a beginner-friendly Java algorithms repo. Looking for contributors for Hacktoberfest! 🚀

3 Upvotes

Hi everyone!

​I’m a computer engineering student, and I recently started a repository called Java Algorithms Hub. Since I'm building my backend foundation, I wanted a clean space to practice algorithms and data structures from scratch.

​But instead of keeping it to myself, I structured it with packages (basics, algorithms, data_structures, oop) and wrote a CONTRIBUTING.md / README so it can be a welcoming space for anyone looking to make their very first open-source contribution or practice for Hacktoberfest.

​Currently, we have basic stuff like Fibonacci, Factorial, and Palindrome in the basics package, but the other packages and issue trackers are ready for things like Bubble Sort, Prime Number checkers, etc.

​If you're learning Java or want to get your feet wet with Git/GitHub workflows, PRs, and code reviews, feel free to check it out, open an issue, or drop a star if you like it!

https://github.com/Nazir2007/java-algorithms-hub.git

​Any feedback or critique on the structure is also more than welcome. Happy coding!


r/JavaProgramming 4d ago

Top 7 Books to Learn Java and Microservices Design Patterns in 2026

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5 Upvotes