boolean (@NotNull CharSequence s1, int start1, int end1, @NotNull CharSequence s2, int start2, int end2) { if (end1 - start1 != end2 - start2) return false; assertRegionIndicesInRange(s1.length(), start1, end1, s2.length(), start2, end2); for (int i = start1, j = start2; i < end1; i++, j++) { if (s1.charAt(i) != s2.charAt(j)) return false; } return true; }