import java.util.Arrays;import static java.lang.System.out;enum Eon { HADEAN, ARCHAEAN, PROTEROZOIC, PHANEROZOIC }public class EnumConstants {    public static void main(String... args) {	try {	    Class<?> c = (args.length == 0 ? Eon.class : Class.forName(args[0]));	    out.format("Enum name:  %s%nEnum constants:  %s%n",		       c.getName(), Arrays.asList(c.getEnumConstants()));	    if (c == Eon.class)		out.format("  Eon.values():  %s%n",			   Arrays.asList(Eon.values()));        // production code should handle this exception more gracefully	} catch (ClassNotFoundException x) {	    x.printStackTrace();	}    }}