public final int indexOf(java.lang.CharSequence csq,int fromIndex){
  if ((_offset + fromIndex + csq.length() - 1) >= (_offset + _length))   throw new IndexOutOfBoundsException(String.format("From Index %d Is Out of Bounds",fromIndex));
  final char c=csq.charAt(0);
  final int csqLength=csq.length();
  for (int i=_offset + fromIndex, end=_offset + _length - csqLength + 1; i < end; i++) {
    if (_array[i] == c) {
      boolean match=true;
      for (int j=1; j < csqLength; j++) {
        if (_array[i + j] != csq.charAt(j)) {
          match=false;
          break;
        }
      }
      if (match) {
        return i - _offset;
      }
    }
  }
  return -1;
}

public final int indexOf ( java . lang . CharSequence csq , int fromIndex ) { if ( ( _offset + fromIndex + csq . length ( ) - 1 ) >= ( _offset + _length ) ) throw new IndexOutOfBoundsException ( String . format ( "From Index %d Is Out of Bounds" , fromIndex ) ) ; final char c = csq . charAt ( 0 ) ; final int csqLength = csq . length ( ) ; for ( int i = _offset + fromIndex , end = _offset + _length - csqLength + 1 ; i < end ; i ++ ) { if ( _array [ i ] == c ) { boolean match = true ; for ( int j = 1 ; j < csqLength ; j ++ ) { if ( _array [ i + j ] != csq . charAt ( j ) ) { match = false ; break ; } } if ( match ) { return i - _offset ; } } } return - 1 ; }
returns the index within this character sequence of the first occurrence of the specified characters sequence searching forward , starting from the specified index
