Engineer Tang's Implementation Study Notes

Jun 2, 2026 · Backend Development

Primary Key Conflicts & ClassNotFound: 1-Minute Debugging Guide to Save Hours

This article provides a systematic troubleshooting guide for two common production errors—primary key conflicts and class-not-found exceptions—covering error identification, one-minute root cause localization steps, practical fixes like ON DUPLICATE KEY UPDATE and dependency scope checks, and real-world prevention tips.