Snack4 JSON Streaming Parser & Auto-Repair Deep Guide

Snack4 is a high-performance Java JSON library whose JsonReader uses a non-recursive state machine to natively support streaming parse and auto-repair, making it ideal for unstable LLM outputs and large NDJSON files. With Feature.Read_AutoRepair enabled, it automatically infers and completes missing symbols in truncated JSON by maintaining an internal type stack. By combining streaming parse with auto-repair, Snack4 ensures downstream business logic receives stable structured objects regardless of upstream data quality.