How to use java.nio on Mac?

Question

I am getting the error "cannot find symbol" on "Path", "FIles", etc. I am using javac and java 1.8.0_20 on Mac OS X 10.9.2 and the Terminal. Thanks.
import java.io.*;
import java.nio.*;
class a{
     public static void main(String args[]) throws IOException{
          Path directorio = "/Users/Josue/Desktop/";
          try {
               DirectoryStream<Path> stream = Files.newDirectoryStream(dir);
               for( Path file: stream ){
                    System.out.println(file.getFileName());
          catch ( DirectoryIteratorException x ){
               System.err.println(x);

Answer 1

Before you answer, I got the solution (from somewhere else), it was because I didn't import explicitly the  classes Files, Paths, etc.
But I don't understand why  .*  didn't work to do it?