Look for qualified this usages in the same class.

Examples:

    Positive example 1:
    private static final String FORMAT = "yyyy-MM-dd HH:mm:ss";
    public String getFormat(Date date){
        SimpleDateFormat dateFormat = new SimpleDateFormat(FORMAT);
        return sdf.format(date);
    }

    Positive example 2:
    private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    public void getFormat(){
        synchronized (sdf){
        sdf.format(new Date());
        ….;
    }

    Positive example 3:
    private static final ThreadLocal DATE_FORMATTER = new ThreadLocal() {
        @Override
        protected DateFormat initialValue() {
            return new SimpleDateFormat("yyyy-MM-dd");
        }
    };