Represents a currency. Currencies are identified by their ISO 4217 currency codes. Visit the ISO web site for more information.

The class is designed so that there's never more than one Currency instance for any given currency. Therefore, there's no public constructor. You obtain a Currency instance using the getInstance methods.

Users can supersede the Java runtime currency data by means of the system property java.util.currency.data. If this system property is defined then its value is the location of a properties file, the contents of which are key/value pairs of the ISO 3166 country codes and the ISO 4217 currency data respectively. The value part consists of three ISO 4217 values of a currency, i.e., an alphabetic code, a numeric code, and a minor unit. Those three ISO 4217 values are separated by commas. The lines which start with '#'s are considered comment lines. An optional UTC timestamp may be specified per currency entry if users need to specify a cutover date indicating when the new data comes into effect. The timestamp is appended to the end of the currency properties and uses a comma as a separator. If a UTC datestamp is present and valid, the JRE will only use the new currency properties if the current UTC date is later than the date specified at class loading time. The format of the timestamp must be of ISO 8601 format : 'yyyy-MM-dd'T'HH:mm:ss'. For example,

#Sample currency properties
JP=JPZ,999,0

will supersede the currency data for Japan. If JPZ is one of the existing ISO 4217 currency code referred by other countries, the existing JPZ currency data is updated with the given numeric code and minor unit value.

#Sample currency properties with cutover date
JP=JPZ,999,0,2014-01-01T00:00:00

will supersede the currency data for Japan if Currency class is loaded after 1st January 2014 00:00:00 GMT.

Where syntactically malformed entries are encountered, the entry is ignored and the remainder of entries in file are processed. For instances where duplicate country code entries exist, the behavior of the Currency information for that Currency is undefined and the remainder of entries in file are processed.

If multiple property entries with same currency code but different numeric code and/or minor unit are encountered, those entries are ignored and the remainder of entries in file are processed.

It is recommended to use BigDecimal class while dealing with Currency or monetary values as it provides better handling of floating point numbers and their operations.