The example is correct. toIndex is exclusive.

Here is Dijkstra's opinion on why:

https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/E...

Aside from the questionable inequalities, there's a missing closing parenthesis after the arguments on the first line, too.

EDIT: as has been pointed out, the inequalities are correct. The original code can e.g. be found here, including doc comments showing the intended meaning of the arguments: http://www.groklaw.net/pdf3/OraGoogletrialexhibits/2012-04-2... (all the way at the end)

The upper bound of the range is intended to be exclusive, while the lower bound is inclusive - basically, the same s array indexing convention. It allows the case where fromIndex == toIndex to represent the empty range (note that this check does permit fromIndex to equal toIndex, but never to exceed it), and the number of entries in a given range is always defined by toIndex - fromIndex.

This is correct for a half-closed interval https://mathworld.wolfram.com/Half-ClosedInterval.html

toIndex is defined to be the index after the last element of the range (a half-closed interval).