Question

I have a project which requires creating Classes dynamically at runtime, where the only information available is the Class name in String form. I’m testing right now with some dead simple Reflection library methods, but my question is, why do I have to provide a fully qualified Class name if the Classes I’m trying to ‘dynamically’ load are in the same directory? I’m using linux, no development environment, just all the Classes I’m trying to invoke in the same directory with no package declarations whatsoever. Do I have to set up a package system to use Reflection? Here’s this little code snippet….

public class ReflectionTest {
    public static void main(String[] args) {
        try {
            Class nodeClass = Class.forName("Node");
            System.out.println(nodeClass.toString());
        } catch (ClassNotFoundException cnfe) {
            System.out.println("Error");
        }
    }
}

Now, this throws the error. But when I create an instance of Node, and then get it’s fully qualified Class name with Node.getClass().getName(), I just get “Node” in return. So I don’t understand why the Reflection library doesn’t work the same as invoking the JVM with ‘java’, where if no package name is supplied it simply looks in the same directory. I’m not sure how to use this library with user-defined Classes when none of my Classes have an associated package name.

Answer 1

Your code should work as described. That is, if you can call new Node() you should also be able to call Class.forName("Node"). I’ve just tried this with a package-less class to verify and everything works as expected.

Is Node.class available in the classpath? You may get this to work by adding the current directory to the classpath.