When given a static set of objects (static in the sense that once loaded it seldom if ever changes) into which repeated concurrent lookups are needed with optimal performanc
I wonder why no one mentioned perfect hashing.
It's only relevant if your dataset is fixed for a long time, but what it does it analyze the data and construct a perfect hash function that ensures no collisions.
Pretty neat, if your data set is constant and the time to calculate the function is small compared to the application run time.