I am receiving a Find Bugs error - call to method of static java.text.DateFormat and I don\'t know the reason why it\'s not good / advisable to be
Commons Lang has a FastDateFormat object that is thread safe. It only does formatting though, not parsing.
If you can use commons-lang this might work well for you.
private static final Date TODAY = Calendar.getInstance().getTime();
private static final FastDateFormat yymmdd = FastDateFormat.getInstance("yyMMdd");
private String fileName = "file_" + yymmdd.format(TODAY);