jp-many-boolean-fields — many boolean fields
Claim
Packing many boolean fields into a bitfield can shrink instances when headers/alignment leave waste. Under Compact Object Headers on JDK 25, 8 booleans and an int flags field both measure 16 bytes — no footprint win for this shape.
How measured
- Harness:
research/Jp009BoolPackJol.java+ JOL 0.17 - Raw:
JP009_BoolPackJol.jsonl
Runtime
| Shape | total_size_bytes (COH) |
|---|---|
| ManyBool (8× boolean) | 16 |
| Packed (int flags) | 16 |
| ratio | 1.0× (no win) |
Policy
hint — footprint claim is situational (Shipilev U-only / many instances / pre-COH). Do not escalate.
Limits
Not a hot-path wall-clock claim. Few-instance types (Activity, Options, Server) already demoted.