The codice_57 and codice_58 classes are really just byte streams with additional processing performed on the data stream to convert the bytes to characters. They use the default character encoding for the platform, which as of J2SE 5.0 is represented by the returned by the static method. The class converts an codice_55 to a codice_57 and the class converts an codice_56 to a codice_58. Both these classes have constructors that support specifying the character encoding to use. If no encoding is specified, the program uses the default encoding for the platform.