FULL PRODUCT VERSION :
java version "1.8.0_92"

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [版本 6.3.9600]
Windows 8.1

A DESCRIPTION OF THE PROBLEM :
When I use SimpleDateFormat("yyyy/ww") to parse the date of "2015-12-31", it returns the week number as 1.

Apparently, this day is in last week of 2015, instead the first one.

I also tried several days before 2015-12-31, and such days of other years, the week number returned is always 1.

PS:
"2015-12-26" produces 2015/52, but
"2015-12-27" produces 2015/01.

Please try the attached code below.

REGRESSION. Last worked in version 8u92

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_92"
Java(TM) SE Runtime Environment (build 1.8.0_92-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.92-b14, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Please run the attached source code to see more details.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Date: 2015/12/31
Week: 2015/53

or

Date: 2015/12/31
Week: 2016/01
ACTUAL -
Date: 2015/12/31
Week: 2015/01

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.text.SimpleDateFormat;
import java.util.Calendar;

public class ReportBug {
public static void main(String[] args) {
SimpleDateFormat
dfDateOnly = new SimpleDateFormat("yyyy/MM/dd"),
dfYearWeek = new SimpleDateFormat("yyyy/ww");

Calendar c = Calendar.getInstance();
c.set(2015, 11, 31);

System.out.println("Date: " + dfDateOnly.format(c.getTime()));
System.out.println("Week: " + dfYearWeek.format(c.getTime()));
}
}
---------- END SOURCE ----------