Feel free to fork into the respositories here. The nice acts of collaboration and sharing are always welcome.
Releases v67 and later of Quarkus is out now!

To prioritise realisable ideas (SMART goals) and realise the top three, I rate them with-
- feasibility study,
- absolute value proposition,
- cost in terms of effort and time, and
- value for money (the returns against risk & investment). RoRI = RoR + RoI
For example, you may have a kind look at the dashboard here:
- Product Architectures: Event-sourced and async APIs, ReSTful APIs, gRPC for streaming, Microservice Architecture, Messaging
- Development & Design: REST Principles, Domain-Driven Design (DDD) & Hexagonal, TDD, Continuous Delivery, DevOps, SOLID, YAGNI, Requirements Engineering (FR+NFR), Scaled Agile, Documentation, JIRA, Testing Automation (Unit + Integration), E2E Testing, UAT
- Languages: Kotlin, Java 25, Multithreading, Kotlin, JavaScript, Bash
- Frameworks, Libraries & Environments: Spring Boot, Quarkus, JAX-RS, Ktor, Jakarta EE, Node.js, Express.js, TypeScript, Hibernate, Spring Security, Spring Cloud, React.js, Angular, Thymeleaf
- Utilities: Kafka, RabbitMQ, JUnit, Playwright, UML, Mockito, Webpack, Babel, Jest, Git, BitBucket (Atlassian), Sentry, Cursor, Claude, IntelliJ IDEA, VS Code, eclipse
- Data Stores: RDBMS (MySQL, PostgreSQL, Oracle, PL/SQL, SQL Scripts), NoSQL (MongoDB, Neo4j, Redis)
- Cloud Platforms: AWS (EC2, S3, RDS, Glue, Kinesis, Athena, Redshift, Lambda, Step Functions, EKS, Fargate, CloudFormation), Azure(VM, Database, Data Factory, DevOps), GCP (Google Storage, Cloud Run, App Engine), Linux, Bash Scripting, Containerization & Orchestration, Podman, Docker, Kubernetes
- CI/CD: Azure DevOps, AWS DevOps, Iac (Terraform, Pulumi), GitHub Actions, Jenkins Pipelines, Gitlab CI, ArgoCD GitOps
- Worflow Automation: Airflow, n8n
- STEM: Computer Science (Data Structures, Algorithms, Automation), Applied Science, Mathematics, Statistics
- Semantic Search: RAG, LangChain, LangGraph, LangChain4j, Vector Embeddings
- Data Analytics & GenAI: ML (Machine Learning) with Python, AI (Artificial Intelligence), LLaMA (Large Language Models), GenAI products (Gemini)
- PoC’s to Implement: Time Schedule Planner, Fleet Management, Multi-Currency Apps, Logistics for e-Commerce, Core Banking, Stocks (Bonds, Derivatives, Dividends), Biochemistry, Patient Care, Pharma (Apotheke)
Let’s create efficient systems and bridge gaps. Experiences will build a life-long experience. Challenges are stepping stones. One must step upon them and progress. 😄
Code samples and PoC's ... for learners and seekers to refer quickly.
I must not mix them among the others by enumerating. So, here are many, many repositories, gists and projects. ROLLING DRUMS!!!
1. Terraform with AWS a PoC to mentor a beginner on Terraform
A new team member as well as an entrant into IaC arena can easily learn and quickly start delivering value with this repository. Its self-explanatory code is enough to couple with Terraform Cloud. Declaring resources with the help of variables is detailed out very well.
2. Chatbot for use with Banking, Insurance or even e-Commerce Marketplace e-Commerce Chatbot, powered with LangGraph, LangChain and ReAct framework
LangGraph-powered Chatbot for e-Commerce platform, with Conversational AI and memory.
3. A personalized Chatbot Chatbot-Langchain PoC
a personalized Chatbot, built with with the following:
- LangChain
- fitz
- OpenAI API
- BeautifulSoup
- Flask
4. RAG: Retrieval-augmented Generation LLM-powered apps (built using LangChain)
Here are featured multiple apps, powered with various libraries and projects under LangChain umbrella, thanks to the comprehensive documentation:
- [LangChain Expression Language] (https://www.langchain.com/blog/langchain-expression-language)
- [output_parsers | langchain_core | LangChain Reference] (https://reference.langchain.com/python/langchain-core/output_parsers)
- [Faiss for similarity search] (https://ai.meta.com/tools/faiss/)
- Retriever integrations - Docs by LangChain
- Build a RAG agent with LangChain - Docs by LangChain
- passthrough | langchain_core | LangChain Reference
5. Football World Cup Scoreboard Scoreboard Easy to Customize for Other Game Genres
It is a data feed library for Live Score Board of Football World Cup. Right now it shows all ongoing football matches from our data feed providers and the live scores updated accordingly.
6. Net Price Calculator Net Price Across Currencies
A comprehensive service for a multinational (or even global) company which operates in any financial domain. It is a service which allows consumers to calculate the net price of a product or service based on its gross price and the prevalent VAT (MWSt) rate. Our calculator also takes into consideration forex rates and performs the foreign currency conversions (foreign exchanges).
7. Leasing: Vehicle Leasing and Returning Leasing
End-User Utility to take vehicles on lease, respect such leasing contracts and returning the leased vehicles to the providers. For use by customers (vehicle users). Screenshots of the revamped UI to attach in next update.

8. Order Management OM
It has three main modules - Product, Order, Inventory - exposing their services with Web Services via synchronous and asynchronous communications. It has been implemented using these tech and tools (and more);
- Spring Boot 3.2, with Spring Web
- Spring Cloud Config (for service integration)
- Spring Security (for Authz-n-Authn)
- Keycloak (for user account management)
- MongoDB (NoSQL Database)
- Spring Data MongoDB (for Mongo Repository)
- MySQL (Relational Database System)
- Spring Data MySQL (for JPA Repository)
- Flyway (for Database Migration)
- Docker-Compose (for containerization)
- Swagger (for OpenAPI-based API documentation)
- Testcontainers (for Test Automation with stubs)
- Rest-Assured (for Testing and Validation)
- Lombok (for boilerplate code injection)
- Spring RestClient (out of Spring Boot)

9. Employee On-Boarding New-Age HRMS
The compact Human Resource management tool for adding talent to build Superteams!!! A must-have accelerator for modern large-scale enterprises. It allows for rapid onboarding of people and reduces error rates.
10. What's available in Java 24 API Link
- improvement in performance and memory management
- security and cryptography
- modernized Java APIs
- JVM changes
- languages and syntax
- more structured concurrency and threading
- deprecation and "end-of-life"
11. What's available in Java 21 API Link
New features available in Java 21 which we missed in Java 17 and earlier versions. Features, which are most notable and stand as the best candidates for frequent use, are listed below:
- Virtual threads (from Java 19)

- Usage of
recordtypes in conditionals. Very useful withif(reference instance Type)tests.
if(publicParameter instanceof SpecificType) {}
- labels for
switchcases. These are very similar toinstanceofchecks.
case TierOne test -> future = test.callActionOne(); case TierTwo test -> future = test.callActionTwo();
- String literals (a preview feature) to build parameterized text strings. These are similar to string literals / template strings of modern JavaScript and f-strings of python. The template processor
STRis automatically imported and is available to use without any explicit import or declaration. More template processors includeRAWandFMT. Remember"fmt"of Go (Golang)?
String vmUserName = localSystem.retrieveUserName();
String helloVitrualWorld = STR."Hola \{vmUserName}";
- One major pathchanger about Java Collection Framework is: the introduction of "sequenced collections":
SequencedCollection,SequencedSetandSequencedMap.
public interface SequencedCollection extends Collection // since 21 public interface SequencedMap extends Map // since 21 public interface SequencedSet extends SequencedCollection, Set // since 21
- My favorite as it is about security and encryption: Key Encapsulation Mechanism (KEP) to secure symmetric keys.
- TODO: Add updated screenshots
- Implementation examples are in the project code under
Java21APIalong with the checklist of which of the features have been tested.
12. Java 17 Examples Link
- restore always-Strict floating-point semantics
- enhanced pseudo-random number generators
- new macOS rendering pipeline
- macOS/AArch64 port
- deprecate the Applet API for removal
- strongly encapsulate JDK internals
- pattern matching for switch (preview)
- remove RMI activation
- sealed classes
- remove the experimental AOT and JIT compilers
- deprecate the Security Manager for removal
- Foreign Function and Memory API (incubator)
- Vector API (second incubator)
- context-specific deserialization filters
13. Java 14 Examples Link
JDK 14 features used in various implementations:
- InstanceofPatternMatching.java : to declare reference for matching object upon checking its type
- NullPointerExceptionPlus.java : to get a more descriptive NPE description
- RecordVsClass.java : to demonstrate and use Record type
- SwitchExpressions.java : to use switch expressions instead of switch statements
- TextBlockVsString.java : to demonstrate a text block literal
14. Java 11 Examples Link
JDK 11 features used in various implementations:
- CollectionPlus.java : to get arrays out of lists
- FilesReadStringWriteString.java : to read from and write to file
- HttpClientPlus.java : to demonstrate HttpClient for GET, POST and PUT request/response handling as in JDK 11
- JavaRunClass.java : to run the Java program with
java JavaRunClass.javacommand form - LambdaLocalVars.java : to demonstrate var for lambda functions
- OptionalIsEmpty.java : to demonstrate Optional.isEmpty()
- StringApiPlus.java : to demonstrate the new methods of String API in Java 11
15. Python: Jupyter Notebooks (.ipynb) Link
- calendar
- cube root
- random module usage
16. Python Scripts and Programs (without Notebooks) Link
- addTwoNums.py
- areaOfTriangleByBaseAndHeight.py
- armstrongNumber.py
- armstrongNumbersInRange.py
- checkEvenOddNumber.py
- checkLeapYear.py
- checkPositiveNegativeZero.py
- checkPrimeNumber.py
- convertKmToMile.py
- convertMileToKm.py
- desktop.ini
- factorial.py
- fibonacciSeries.py
- generateRandomNumber.py
- largestNumberQuiz.py
- largestOfThreeNumbers.py
- main.py
- multiplicationTable.py
- o2c_otc.pdf
- passwordGenerator.py
- powersOfTwo.py
- printHelloWorld.py
- printPrimeNumberInSomeRange.py
- readPdfFileOut.py
- squareRoot.py
- swapTwoNumbers.py
- temperatureCelToFahr.py
17. LeetCode Problems Solved Link
- LC01TwoSum.java : Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
- LC02AddTwoNumbers.java : Given two non-empty linked lists representing twonon-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.
- LcMaxConsecutiveOnes.java : to find the length of the longest subsequence having only 1's else to return 0
- LcSeptemberLeetcodingChallenge2021Week4.java : [WIP] to get the maximum length of possible words made with the segments provided in input arrays, with the condition that no letters in the words must be repeated anyhow And more on the way!
18. RRShopware Link
- an interactive page/view of shopping site implementation with vanilla JavaScript, CSS and HTML
- To visit the cloud-hosted site, smile and step in to RRShops
19. Various Popular Algorithms Implemented in Java and PoC's for explaining the Features of Java Core API's Link
- The list of Concurrent Collections and more components available as part of Concurrency API in Java 8 and later, such as Executor, ExecutorService, Lock and Symaphore.
- DefaultEleValue.java : to test default values of elements of array
- MedianOfTwoArrays.java : to find the median for the elements of two arrays taken together
- SecondLargest.java : to find second largest element in an array of integers
- FindDuplicatesInArrayByMap.java : to find duplicate elements in an array
- FindDuplicatesInArrayByStream.java : to find duplicate elements in an array
- StreamCollectMethods.java : to demonstrate various use scenarios of Stream.collect() method with Collectors And more to come up!
20. [GIST] HTTP response status codes Link
- Status Codes for frequently used HTTP responses. Very useful and crisp list of the response codes for web development.
21. [GIST] Java 8 DateTime code samples Link
- Code fragments for learners to refer and use quickly frequently used methods out of new Java DateTime API in Java 8+.
22. [GIST] Java Stream Collector/Collectors methods to Collect Streaming Data Link
- Code fragments for learners to learn and use efficiently all of the end-user-level methods of Java Stream API in Java 8+.
23. [GIST] Functional Interfaces in Java API Link
- It lists various in-built interfaces and their respective methods for functional programming using Java 8+.
24. [GIST] Java Concurrency API, Concurrent Collections and Synchronizers in Java Link
- The list of Concurrent Collections and more components available as part of Concurrency API in Java 8 and later, such as Executor, ExecutorService, Lock and Symaphore.
- Docker networking across OSI Model layers of networks,
- hosting the containers in cloud infrastructure as well as in virtual networks,
- orchestrating clusters using Kubernetes, local registries and IaC tools, and
- Apache NiFi for data flow and application testing.
🤔 I have always been curious about Green Development by enhancing system performance. To me, the easiest approach to achieve Sustainability is:
- to write highly performant applications, services and platforms.
- In case I fall short of the SME level of expertise regarding some tools, I rely on the promises of the respective providers. They include the leading cloud service providers.
- These repositories present the resources being developed continuously as well as ready projects. Hence keep on pulling and sync'ing regularly.
- And, yes, continuous development and continuous integration are obviously good.
- LinkedIn Messaging: https://www.linkedin.com/in/rishirajopenminds
- X Byte: https://twitter.com/RishiRajDevOps
- DockerHub: <i50729 @ DockerHub)>
- Start Page: https://bio.link/rishiraj49de
- GitHub: https://github.com/rishiraj88
I thank all who have mentored, taught and guided me. Also, I appreciate who have supported my work with pair programming, extreme programming and more.




