Classnotfoundexception class.forName()

[Gina vernon]

Hi,
I am trying to use reflection to get a specific instance of a class. But I have found that both class.forName and ClassLoader.loadClass method throw a classnotfoundexception.
here's the code:

 
          ClassLoader myClassLoader = LDAPManager.class.getClassLoader();
          ClassLoader parentClassLoader = LDAPManager.class.getClassLoader().getParent();
          System.out.println(myClassLoader.getClass());
          System.out.println(parentClassLoader.getClass());
          Class otherClassInstance = Class.forName(LDAPManager.class.getName(), false, parentClassLoader)
          Method getInstanceMethod = otherClassInstance.getDeclaredMethod("getInstance", new Class[] { });

stacktrack

  java.lang.ClassNotFoundException: test.hib.util.LDAPManager
	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
	at sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:247)
	at test.hib.Class1.main(Class1.java:25)
  

Thanks.

[shan raj]

Check your class path where you are running program has pointed LDAPManager class or its jar.

[Rob Spoor]

That would probably solve it. I'm wondering why you are loading the class dynamically if you can also load it statically; since you are already using LDAPManager.class, why not simply use LDAPManager.getInstance()? Or is LDAPManager's class loader a custom one (URLClassLoader perhaps), and you want to load the class again? Then I have bad news for you: if the parent class loader could load the class, it already would have, and otherClassInstance == LDAPManager.class (provided it worked). If the parent class loader couldn't load the class before, it still can't now.

So either in the end, otherClassInstance == LDAPManager.class, or there will be a ClassNotFoundException.

To prevent this, either add the JAR file to your class path (in which case you can just use LDAPManager.getInstance()), or create a new class loader to load the class.