public abstract Class CharsetProvider

A charset provider is a concrete subclass of this class that has a zero-argument constructor and some number of associated Charset implementation classes. Charset providers are deployed on the application module path or the application class path. In order to be looked up, charset providers must be visible to the system class loader. See Deploying Service Providers for further detail on deploying a charset provider as a module or on the class path.

For a charset provider deployed in a module, the provides directive must be specified in the module declaration. The provides directive specifies both the service and the service provider. In this case, the service is java.nio.charset.spi.CharsetProvider.

As an example, a charset provider deployed as a module might specify the following directive:

provides java.nio.charset.spi.CharsetProvider with com.example.ExternalCharsetProvider;

For a charset provider deployed on the class path, it identifies itself with a provider-configuration file named java.nio.charset.spi.CharsetProvider in the resource directory META-INF/services. The file should contain a list of fully-qualified concrete charset-provider class names, one per line. A line is terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a line feed. Space and tab characters surrounding each name, as well as blank lines, are ignored. The comment character is '#' ('\u0023'); on each line all characters following the first comment character are ignored. The file must be encoded in UTF-8.

If a particular concrete charset provider class is named in more than one configuration file, or is named in the same configuration file more than once, then the duplicates will be ignored. The configuration file naming a particular provider need not be in the same jar file or other distribution unit as the provider itself. The provider must be accessible from the same class loader that was initially queried to locate the configuration file; this is not necessarily the class loader that loaded the file.