Fourteen years of Java backends. Notes on what broke and what shipped.

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Java architect

14+
Years with Java
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BioScope3D lab
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Architecture · Java

Monolith splits, release trains, and the week the cluster went quiet.

Fourteen years in e-commerce, fintech, and internal SaaS backends. Auth boundaries, Jenkins pipelines, and what "done" actually means.

Done means running live, not merged to main.

Topics I write about

Ops & debugging

Jenkins speed-ups, JVM tuning, SQL plans, and postmortems worth filing.

Jenkins · JVM · MySQL

Data platforms

Hive layers, Flink jobs, and metrics APIs the business queries on Monday.

Hive · Flink · ClickHouse

Blog

How I think about backend work

Prefer boring systems that stay up.

If the on-call engineer can patch it at 3 a.m. without a runbook novel, the design is working.

Write with specifics.

One incident with timestamps beats a list of best practices. Names, configs, and what you rolled back.

Stack is context, not identity.

The same Spring Boot codebase behaves differently in e-commerce, fintech, and internal SaaS teams.

Side projects

About

Wu Jinsen writes Java backends—fourteen years across e-commerce, fintech, and SaaS, microservices, data warehouses, and teams. BioScope3D is a WebGL side lab.