Question

I have a program where I compile java code that somebody writes in a text box, and run it.
They type out the full source code, class and all

I save the class they write to a random java source file, and then compile and load the class through a classloader. This works perfectly.

I have a new issue though, that of sub classes. I give the outer class a unique name, and load that class.

Ex.

TEMP1110.java -> TEMP1110.class, etc.
With inner classes, it compiles to TEMP1110$InnerClass.class
I try loading this class through my class loader, but when the outer class makes a call to it: new InnerClass().method();

it gives me this: java.lang.NoClassDefFoundError: TEMP1110$InnerClass

Is there some quirk or something I am doing wrong?

My classloader:

private static class JClassLoader extends ClassLoader {
    public Class buildClass(final byte[] data, final String className) {
        return (Class) defineClass(className, data, 0, data.length);
    }
}

className being TEMPCLASS$InnerClass, and data being the bytes that represent the class file. This works for outer classes.

Answer 1

My eventual solution, with I being the interface:

ClassLoader cl = new URLClassLoader(new URL[] {new File("TEMP/").toURI().toURL()});
Class classd = cl.loadClass(className);
return (I) classd.newInstance();

Previously, I was using some older documentation that just complicated the whole process.