Dynamic loading of a class at runtime with known inheritance

Question

Hi,
I am trying to dynamically load a class during runtime where I know that the class implements a particular interface 'AInterface'. Also, this class may be linked to other classes in the same package as that class, with their implementations/extensions given in their particular definitions.
The class is found by using a JFileChooser to select the class that implements 'AInterface', and loaded up.
Because the name of the class can be practically anything, my current approach only works for certain classes under the package 'Foo' with classname 'Bar'. Some names have been changed to keep it abstract.
private AInterface loadAInterface(URL url) throws Exception {
     URL[] urls = { url };
     // Create a new class loader with the directory
     URLClassLoader cl = new URLClassLoader(urls);
     // Load in the class
     Class<?> cls = cl.loadClass("Foo.Bar");
     return (AInterface) cls.newInstance();
}As you can see, all that is being returned is the interface of the class so that the interface methods can be accessed. My problem is that I don't know what the class or package is called, I just know that the class implements AInterface. Also note that with this approach, the class itself isn't selected in the JFileChooser, rather the folder containing Foo/Bar.class is.

Answer 1

ejp wrote:
The class is found by using a JFileChooser to select the class that implements 'AInterface', and loaded up.
Also note that with this approach, the class itself isn't selected in the JFileChooser, rather the folder containing Foo/Bar.class is.These two statements are mutually contradictory...My apologies, I worded that wrong. My current approach (the one given in the code) selects the root package folder. However, what I want to be able to do, is to simply select a single class file. The current code just makes some assumptions so that I can at least see results in the program.
As you said, if the root of the package hierarchy is known, then this could be achieved. The problem is that the user either selects the package root or the AInterface class, but not both.
Is there a way to get package details from a .class file to be used in the actual loading of the class?