Code Archaeology

Jul 28, 2026 · Backend Development

How Jackson Rewrote Buffer Pooling for Java Virtual Threads

Jackson replaced its ThreadLocal-based buffer recycling with a pluggable RecyclerPool abstraction, iterated through multiple default pool implementations including a flawed LockFreePool, removed the leaky LockFreePool in 3.x, and fixed a TOCTOU race in BufferRecycler using atomic updates.