Hutool 3.9 Upd May 2026

The Patch That Saved the Stack Trace

In the bustling digital city of Javaopolis, there was a library that everyone loved but few truly understood. Its name was Hutool.

1. Run your test suite and note deprecation warnings or compile errors.
2. Replace deprecated methods with suggested alternatives in compiler javadocs.
3. For HTTP client code, review timeout, pooling, and SSL settings; adopt new configuration objects where applicable.
4. For Excel-heavy workflows, test large-file read/write for performance/regression.
5. Verify JSON conversions, especially for custom serializers/deserializers.

Li Xiaohong never released another .UPD version. He once said in a conference talk, "I made 3.9.UPD because perfection doesn't arrive on a schedule. It arrives when you stop adding things and start fixing what matters." Hutool 3.9 UPD

6. JsonUtil (Jackson integration)

• Better Jackson ObjectMapper customization hooks
• Pretty-print toggle

• Benefit: Bug fixes, security patches, and performance gains.
• Cost: Requires refactoring Date handling code (if moving to Java 8 time API) and updating package imports.

Extended OS Support: Support for newer environments like Windows 11. The Patch That Saved the Stack Trace In