SimpleDateFormat parsing "yyyy-M-dHH:mm:ss" error

A DESCRIPTION OF THE PROBLEM :
code:
String date = "2021-2-23";
String time = "09:30:31";
System.out.println(new SimpleDateFormat("yyyy-M-dHH:mm:ss").parse(date+time));
System.out.println(new SimpleDateFormat("yyyy-M-d HH:mm:ss").parse(date+" "+time));
System.out.println(System.getProperty("java.version"));


output:
Sun Feb 14 21:30:31 CST 2021
Tue Feb 23 09:30:31 CST 2021
11.0.11

FREQUENCY : always