Collections.binarySearch() vs. List indexOf()

Question

I have a list of more than 37K items, and I already implemented hashCode(), equals(), so I wonder Collections.binarySearch() can help

Answer 1

in order for binarySearch() to work, your list must be sorted. equals() and hashCode() have nothing to do with sorting. your objects need to be Comparable, or you must have a relevant Comparator. either way, you must sort the List first.

and yes, assuming the list is sorted, then you will probably get better performance from binarySearch() as compared to indexOf().