ParsePosition getErrorIndex returns 0 for TimeZone parsing problem

FULL PRODUCT VERSION :
java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b25)
Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
DarwinMacBook-Pro-7.local 14.3.0 Darwin Kernel Version 14.3.0: Mon Mar 23 11:59:05 PDT 2015; root:xnu-2782.20.48~5/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
reporting on behalf a Stack Overflow user:
http://stackoverflow.com/questions/30076349/simpledateformat-parse-returns-errorindex-as-0

a malformed TimeZone will prevent parsing the date, but not set the correct errorIndex in ParsePosition

REGRESSION. Last worked in version 6u43

ADDITIONAL REGRESSION INFORMATION:
claimed to be working in at least jdk1.6.0_38

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
run the attach source code

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
parse position for error should be 21
ACTUAL -
parse position for error is 0, the date was not parsed. Provind for example an invalid month name does produce a correct error position of 3

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
  public static void main(String[] args) throws Exception {
    String date = "13 Jan 2005 21:45:34 ABC";
    String format = "dd MMM yyyy HH:mm:ss z";
    ParsePosition pp = new ParsePosition(0);
    pp.setIndex(0);
    SimpleDateFormat sd = new SimpleDateFormat(format, Locale.ENGLISH);
    Date d = sd.parse(date, pp);
    System.out.println(d);
    System.out.println("Error Index " + pp.getErrorIndex());
  }
---------- END SOURCE ----------