ClassLoader only loads root directory class???

Question

I tried to load an external class in Java application, but I found
out I can only put the external class in root directory C:\
Otherwise, it will throw class not found exception. any ideas???
ClassLoader loader = new PluginClassLoader(Integer.parseInt(key));
//Class c = loader.loadClass("C:\\proj\\NewMenu"); //throw class not found exception
Class c = loader.loadClass("NewMenu"); //search for C:\NewMenu.class

Answer 1

Make sure the class file you are trying to load is in your classpath (which is usually the JDK class path along with the base folder for any packages that you wrote, including '.').
If you're sure the class files are in the class path, then try getting your ClassLoader like:
    ClassLoader loader = ClassLoader.getSystemClassLoader();I don't know much about ClassLoaders at all (or PluginClassLoader either), but maybe the system one is set up to look in your classpath, whereas ones you create are not.
I can tell you know, though, that passing "C:\\proj\\NewMenu" isn't going to work. Java is designed to be platform independent, and that type of pathname is Microsoft-specific. If you have classes in subfolders of one of your class path folders, you need to make sure you declare them to be in the appropriate package, and you need to load them as "whatever.my.package.ClassName". What I mean is, say "c:\classes" is in your classpath. If you have a set up like:
c:\
  classes\
    class1.class
    misc\
      class2.class
      class3.class
      other\
        class4.classThen you need to make sure that, when you compiled each of those classes, you put "package misc.other;" or whatever at the top of the source file. And, say you wanted to load class4 with your ClassLoader, you'd have to do loader.loadClass("misc.other.class4").
Sorry I couldn't give you better advice.
Jason