Description
The javadoc's examples show how indexOf should work not lastIndexOf.
StringUtils.lastIndexOf(null, *) = -1
StringUtils.lastIndexOf(*, null) = -1
StringUtils.lastIndexOf("", "") = 0
StringUtils.lastIndexOf("aabaabaa", "a") = 0
StringUtils.lastIndexOf("aabaabaa", "b") = 2
StringUtils.lastIndexOf("aabaabaa", "ab") = 1
StringUtils.lastIndexOf("aabaabaa", "") = 8