ADDITIONAL SYSTEM INFORMATION :
64-bit Operating System
Windows 10
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)

A DESCRIPTION OF THE PROBLEM :
SimpleDateFormat normalizing the date to next next month date when we input as invalid date.

REGRESSION : Last worked in version 8u192

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateTest {

    public static void main(final String[] args) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd");
        dateFormatter.setLenient(true);
        Date parse = null;
        try {
            parse = dateFormatter.parse("2018-06-31");
        } catch (ParseException e) {
            System.out.println("Parsing exception :" + e.getMessage());
        }
        System.out.println(parse);
    }
}

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expecting parsing exception since it is invalid date. In july 31st date doesn't exist
ACTUAL -
Sun Jul 01 00:00:00 IST 2018

CUSTOMER SUBMITTED WORKAROUND :
Using LocalDate for conversion
DateTimeFormatter f = DateTimeFormatter.ISO_LOCAL_DATE;
LocalDate ld = LocalDate.parse("2018-06-31", f);
Caused by: java.time.DateTimeException: Invalid date 'JUNE 31'

FREQUENCY : always