DummyInvocationUtils.methodOn() Enhanced Controllers Throw NPE on Methods with void Return

When calling a controller method that returns void on a controller that has been enhanced with DummyInvocationUtils.methodOn(), a null pointer exception is thrown.

What led to this discovery was that I was looking for a way to write a utility method similar to WebMvcLinkBuilder.methodOn() for being able to build links with the faux-call style, except one that would work with controller methods that return void.

public class DummyTest {
    @Test
    public void dummy() {
        Controller dummyController = DummyInvocationUtils.methodOn(Controller.class);
        dummyController.deleteWidget(123L);
    }

    @RestController
    @RequestMapping("/dummy")
    public static class Controller {
        @DeleteMapping("/{id}")
        public void deleteWidget(@PathVariable("id") Long id) {

        }
    }
}

Unexpected AOP exception; nested exception is java.lang.NullPointerException
org.springframework.aop.framework.AopConfigException: Unexpected AOP exception; nested exception is java.lang.NullPointerException
	at app//org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:215)
	at app//org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:110)
	at app//org.springframework.hateoas.server.core.DummyInvocationUtils.getProxyWithInterceptor(DummyInvocationUtils.java:165)
	at app//org.springframework.hateoas.server.core.DummyInvocationUtils.access$000(DummyInvocationUtils.java:38)
	at app//org.springframework.hateoas.server.core.DummyInvocationUtils$InvocationRecordingMethodInterceptor.invoke(DummyInvocationUtils.java:90)
	at app//org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
	at app//org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750)
	at app//org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:692)

Reproduce the provided DummyTest with DummyInvocationUtils.methodOn() and the void Controller.deleteWidget method. Then inspect DummyInvocationUtils.getProxyWithInterceptor and InvocationRecordingMethodInterceptor, both named in the stack trace. Done means invoking the void method completes without the reported NullPointerException.