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 ThreadLocalDATE_FORMATTER = new ThreadLocal () { @Override protected DateFormat initialValue() { return new SimpleDateFormat("yyyy-MM-dd"); } };