Short notes from backend work I have done in real business systems.
These are not open-source code samples. Some of the work was done in private company codebases, so I am keeping the notes limited to responsibilities, troubleshooting approach, technical trade-offs, and lessons learned.
- Java/Spring backend work in healthcare systems beyond local development
- Regional delivery work where the same product needed controlled customisation
- Production troubleshooting using logs, database evidence, and deployment topology
- SQL performance work using Oracle AWR and execution plans
- Awareness of confidentiality when discussing private company systems
Multi-region delivery work for a cloud pharmacy management and healthcare insurance settlement system used by designated pharmacies and outpatient clinics.
How I approached slow settlement APIs during business hours using Oracle AWR snapshots, execution plans, query rewrites, and targeted indexes.
A production issue that appeared after moving from a single application node to a multi-node deployment behind Nginx.
My main production background is Java/Spring backend development in healthcare systems, with work across regional deployments, integration with external platforms, database troubleshooting, Linux deployment, and post-release support.
The goal of this repository is simple: show how I think through real backend work without exposing private source code or customer details.
Java 8, Spring Boot, Spring Cloud, Nacos, Gateway, OAuth2/JWT, Feign, Dubbo, Oracle, MyBatis/MyBatis Plus, Redis, Elasticsearch, Vue 2, Element UI, GitLab, Jenkins, Linux, Nginx, Tomcat, Maven, Git, Postman, PL/SQL.
No proprietary code, internal interface documents, credentials, database schema, customer records, logs, or screenshots are included here.