Call to 'substring(0, matnrStr.length())' is redundant less... (Ctrl+F1)，

Call to 'substring(0, matnrStr.length())' is redundant less... (Ctrl+F1)，

 

String matnrs = matnrStr.substring(0, matnrStr.length());

Call to 'substring(0, matnrStr.length())' is redundant less... (Ctrl+F1) 
redundant被裁减的 多余的操作
Reports a variety of redundant String-related operations like calling String.toString() or String.substring(0).

应该这样写
String matnrs = matnrStr.substring(0, matnrStr.length()-1);