l2j-server-game/dist/game/config/IdFactory.properties

# ---------------------------------------------------------------------------
# ID Factory Settings
# ---------------------------------------------------------------------------
# Warning: 
# Please take extreme caution when changing anything. Also please understand what you are changing before you do so on a live server.

# ---------------------------------------------------------------------------
# Standard Settings
# ---------------------------------------------------------------------------

# Tell server which IDFactory Class to use:
# Compaction = Original method
# BitSet = One non compaction method
# Stack = Another non compaction method
# Default: BitSet
IDFactory = BitSet

# Check for bad ids in the database on server boot up.
# Much faster load time without it, but may cause problems.
# Default: True
BadIdChecking = True