Use CGLib on final classes

TestCGLib.java

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;

public class TestCGLib {

    public static void main(String[] args) {

        try {
            Person person = createProxy(Person.class);
            person.doPrint();
        } catch (IllegalArgumentException ex) {
            System.out.println(ex);
        }

        try {
            System.out.println("-------------------------");
            PersonWithFinalMethods personWithFinalMethods = createProxy(PersonWithFinalMethods.class);
            personWithFinalMethods.doPrint();
            personWithFinalMethods.finalDoPrint();
        } catch (IllegalArgumentException ex) {
            System.out.println(ex);
        }
        try {
            System.out.println("-------------------------");
            FinalPerson finalPerson = createProxy(FinalPerson.class);
            finalPerson.doPrint();
            finalPerson.finalDoPrint();
        } catch (IllegalArgumentException ex) {
            System.out.println(ex);
        }
    }

    @SuppressWarnings("unchecked")
    private static <T> T createProxy(Class<T> klass) {
        return (T) Enhancer.create(klass, new MethodInterceptor() {
            @Override
            public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
                System.out.println("before");
                Object o = proxy.invokeSuper(obj, args);
                System.out.println("after");
                return o;
            }
        });
    }

    static final class FinalPerson {
        final void finalDoPrint() {
            System.out.println("FinalPerson::finalDoPrint");
        }

        void doPrint() {
            System.out.println("FinalPerson::doPrint");
        }
    }

    static class PersonWithFinalMethods {

        final void finalDoPrint() {
            System.out.println("PersonWithFinalMethods::finalDoPrint");
        }

        void doPrint() {
            System.out.println("PersonWithFinalMethods::doPrint");
        }
    }

    static class Person {

        void doPrint() {
            System.out.println("Person::doPrint");
        }
    }
}
//// Output:
/*
before
Person::doPrint
after
-------------------------
before
PersonWithFinalMethods::doPrint
after
PersonWithFinalMethods::finalDoPrint
-------------------------
java.lang.IllegalArgumentException: Cannot subclass final class TestCGLib$FinalPerson
*/