👋 Writing software since 2008, mostly Java backend since 2015. I keep ending up under the API surface — framework source, format specs, packet captures, kernel knobs — and that's the part I find most interesting.

• A patch in MySQL Connector/J 8.0.32 (Bug #108414) — BIT was sitting in a commented-out block of the type switch, falling through to the string default and generating malformed COM_STMT_EXECUTE packets. Caught during a Spring Boot upgrade — Wireshark showed the malformed packets, the MySQL client/server protocol spec told me which field was wrong, and the Connector/J source confirmed it. Oracle was kind enough to ship the fix — moving BIT into the BOOLEAN/TINYINT group.
• jackson-dataformat-spreadsheet — A first-class Jackson dataformat module for Excel, built the way Jackson's own format modules are built. Extends JsonFactory / ParserMinimalBase / GeneratorBase directly, implements OOXML SpreadsheetML, and bypasses POI's User Model on the hot path. Listed in FasterXML community modules, on Maven Central.

• nf_conntrack table filling up — one HAProxy fronting every backend, all stats clean, only the kernel was logging it.
• Tomcat threads stuck on keep-alive — 508 of 512 AJP threads idle in socketRead0(), with the Acceptor blocked at LimitLatch.countUpOrAwait(). jstack -F showed it, Bugzilla #53173 explained it, NIO fixed it.