What's wrong with the method Package.getPackages() ?

Question

Hello,
has anyone an idea why this code doesn't print "java.sql" and other packages' names ?
for (Package pack : Package.getPackages()) {
     System.out.println(pack.getName());
}this is what figures in the javadoc :
public static Package[] getPackages()
Get all the packages currently known for the caller's ClassLoader instance. Those packages correspond to classes loaded via or accessible by name to that ClassLoader instance. If the caller's ClassLoader instance is the bootstrap ClassLoader instance, which may be represented by null in some implementations, only packages corresponding to classes loaded by the bootstrap ClassLoader instance will be returned.
Returns:
a new array of packages known to the callers ClassLoader instance. An zero length array is returned if none are known.
thank you..

Answer 1

Well, I find my self a solution !
there is it :
public final static String apiJarName = "rt.jar";
/* Gives the path of rt.jar */
public static String getAPIPath() {
     String paths[] = System.getProperty("sun.boot.class.path").split(System.getProperty("path.separator"));
     String APIPath = "";
     int i=0;
     while (APIPath.equals("")) {
          if (paths.endsWith(apiJarName)) {
               APIPath = paths[i];
          else {
               i++;
     return APIPath;
/* Gives the list of packages that a mentioned package contains */
public static ArrayList<String> getPackageList(String packageName) {
     try {
          ArrayList<String> packageList = new ArrayList<String>();
          JarFile apiJar = new JarFile(getAPIPath());
          Enumeration<JarEntry> entries = apiJar.entries();
          while (entries.hasMoreElements()) {
               String entry = entries.nextElement().getName();
               if (entry.startsWith("java")) {
                    String pack = entry.substring(0, entry.lastIndexOf("/")).replaceAll("/", ".");
                    if (!packageList.contains(pack)) {
                         packageList.add(pack);
          apiJar.close();
          return packageList;
     catch (IOException e) {
          return null;
}thanks too much *JoachimSauer* and *tschodt*, I couldn't done it without you :)