Method to dynamically load java class files

Question

What would be a good way to dynamically load java class files so that a program compiled into a jar can read all the class files in a directory and use them, and how can one write the files so that they have the necessary package name in relation to the jar?

Answer 1

I believe it's a ClassLoader you're after.

I suggest you start by looking at the example below which loads class files that are not on the class path.

// Create a File object on the root of the directory containing the class file File file = new File("c:\\myclasses\\");  try {     // Convert File to a URL     URL url = file.toURI().toURL();          // file:/c:/myclasses/     URL[] urls = new URL[]{url};      // Create a new class loader with the directory     ClassLoader cl = new URLClassLoader(urls);      // Load in the class; MyClass.class should be located in     // the directory file:/c:/myclasses/com/mycompany     Class cls = cl.loadClass("com.mycompany.MyClass"); } catch (MalformedURLException e) { } catch (ClassNotFoundException e) { }