FieldPosition

FieldPosition is a simple class used by Format and its subclasses to identify fields in formatted output. Fields can be identified in two ways:

• By an integer constant, whose names typically end with _FIELD. The constants are defined in the various subclasses of Format.
• By a Format.Field constant, see ERA_FIELD and its friends in DateFormat for an example.

FieldPosition keeps track of the position of the field within the formatted output with two indices: the index of the first character of the field and the index of the last charac