techblog 

package uk.nominet.testing;
 
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
 
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
 
/**
 * Stub spring bean factory class. Call createStubBean("classname") to stub out a bean.
 */
public class StubBeanFactory
{
    /**
     * Factory method to create stub beans.
     * @param className to create a stub bean for.
     * @return stub bean.
     * @throws ClassNotFoundException if className doesn't match a real class.
     */
    @SuppressWarnings("Unchecked")
    public <T> T createStubBean(String className) throws ClassNotFoundException
    {
        // get the class to proxy
        Class<T> proxyClass = (Class<T>)Class.forName(className);
 
        // the specifics of proxy creation depend upon whether we need to proxy a class
        // or an interface - which is it?
 
        if (proxyClass.isInterface())
        {
            // proxying interfaces is easy with the standard java proxying classes
            return (T)Proxy.newProxyInstance(proxyClass.getClassLoader(),
                                             new Class[]{proxyClass},
                                             new StubMethodHandler());
        }
        else
        {
            // proxying classes requires some cglib magic...
            Enhancer enhancer = new Enhancer();
            enhancer.setSuperclass(proxyClass);
            enhancer.setCallback(new StubMethodHandler());
            return (T)enhancer.create();
        }
    }
 
    /**
     * Helper class to handle method invocations on stub beans.
     */
    private static class StubMethodHandler implements InvocationHandler, MethodInterceptor
    {
        /**
         * @see InvocationHandler#invoke(Object, Method, Object[])
         */
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
        {
            // you could put some logging here...
        }
 
        /**
         * @see MethodInterceptor#intercept(Object, Method, Object[], MethodProxy)
         */
        public Object intercept(Object o, 
        			Method method, 
				Object[] objects, 
				MethodProxy methodProxy) throws Throwable
        {
            // you could put some logging here...
        }
    }
}

<beans>
    ...
    <!-- this is our stub bean factory -->
    <bean id="stubBeanFactory" class="uk.nominet.testing.StubBeanFactory"/>
 
    <!-- stubbing out either interfaces or classes is exactly the 
         same - just call the factory -->
    <bean id="tokenDao"
          factory-bean="stubBeanFactory"
          factory-method="createStubBean">
        <constructor-arg value="uk.nominet.authentication.TokenDao"/>    
    </bean>
    ...
</beans>