code: private Integer conect_helper (String line,int start,int end) {
  		if (line.length() < end) return null;
  
  		String sbond = line.substring(start,end).trim();
  		int bond  = -1 ;
  		Integer b = null ;
  
  		if ( ! sbond.equals("")) {
  			bond = Integer.parseInt(sbond);
  			b = new Integer(bond);
  		}
  
  		return b ;
  	}
docs: safes repeating a few lines ...