FULL PRODUCT VERSION :
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)

A DESCRIPTION OF THE PROBLEM :
The following methods in DateFormat should specify the behavior of passing null as parameters:

format(Date date)
@throws NullPointerException if date is null

format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
@throws NullPointerException if any of the parameters is null

parse(String source)
@throws NullPointerException if source is null

parse(String source, ParsePosition pos)
@throws NullPointerException if any of the parameters is null

setTimeZone(TimeZone zone)
@throws NullPointerException if zone is null


REPRODUCIBILITY :
This bug can be reproduced always.