code: public static boolean containsIgnoreCase(CharSequence sequence, CharSequence subSequence) {
      // Calling length() is the null pointer check (so do it before we can exit early).
      int length = sequence.length();
      if (sequence == subSequence) {
        return true;
      }
      // if subSequence is longer than sequence, it is impossible for sequence to contain subSequence
      if (subSequence.length() > length) {
        return false;
      }
      return indexOfIgnoreCase(sequence, subSequence) > -1;
    }
docs: Indicates whether the character sequence {@code sequence} contains the {@code subSequence},
  ignoring the case of any ASCII alphabetic characters between {@code 'a'} and {@code 'z'}
  or {@code 'A'} and {@code 'Z'} inclusive.
  
  @since NEXT