#1646 - Avoid trying to proxy Object for controller method dummy invocations.

On JDK 17, trying to proxy Object doesn't work anymore. We now simply return the interceptor that would've been applied to the proxy directly and detect that properly in requests to extract the LastInvocationAware instance.

src/main/java/org/springframework/hateoas/server/core/DummyInvocationUtils.java

@@ -144,13 +144,24 @@ public class DummyInvocationUtils {
 	 */
 	@Nullable
 	public static LastInvocationAware getLastInvocationAware(Object source) {
-		return (LastInvocationAware) ((Advised) source).getAdvisors()[0].getAdvice();
+
+		if (InvocationRecordingMethodInterceptor.class.isInstance(source)) {
+			return LastInvocationAware.class.cast(source);
+		}
+
+		return (LastInvocationAware) (Advised.class.isInstance(source)
+				? ((Advised) source).getAdvisors()[0].getAdvice()
+				: source);
 	}
 
 	@SuppressWarnings("unchecked")
 	private static <T> T getProxyWithInterceptor(Class<?> type, InvocationRecordingMethodInterceptor interceptor,
 			ClassLoader classLoader) {
 
+		if (type.equals(Object.class)) {
+			return (T) interceptor;
+		}
+
 		ProxyFactory factory = new ProxyFactory();
 		factory.addAdvice(interceptor);
 		factory.addInterface(LastInvocationAware.class);
@@ -207,6 +218,11 @@ public class DummyInvocationUtils {
 			return result;
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
 		public String toString() {
 
 			return "DummyInvocationUtils.CacheKey(type=" + this.type + ", arguments=" + Arrays.deepToString(this.arguments)

src/test/java/org/springframework/hateoas/server/mvc/DummyInvocationUtilsUnitTest.java

@@ -19,8 +19,11 @@ import static org.assertj.core.api.Assertions.*;
 import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.*;
 
 import org.junit.jupiter.api.Test;
+import org.springframework.aop.framework.Advised;
 import org.springframework.hateoas.Link;
 import org.springframework.hateoas.TestUtils;
+import org.springframework.hateoas.server.core.DummyInvocationUtils;
+import org.springframework.hateoas.server.core.LastInvocationAware;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
@@ -48,6 +51,16 @@ class DummyInvocationUtilsUnitTest extends TestUtils {
 		assertThat(link.getHref()).isEqualTo("http://localhost/sample/2/bar");
 	}
 
+	@Test // #1638
+	void doesNotTryToProxyObject() {
+
+		Object result = methodOn(SampleController.class).methodReturningObject();
+
+		assertThat(result).isInstanceOf(LastInvocationAware.class);
+		assertThat(result).isNotInstanceOf(Advised.class);
+		assertThat(DummyInvocationUtils.getLastInvocationAware(result)).isSameAs(result);
+	}
+
 	@RequestMapping("/sample")
 	static class SampleController {
 
@@ -60,5 +73,9 @@ class DummyInvocationUtilsUnitTest extends TestUtils {
 		HttpEntity<Void> someOtherMethod(@PathVariable(name = "otherName") Long id) {
 			return new ResponseEntity<>(HttpStatus.OK);
 		}
+
+		Object methodReturningObject() {
+			return Void.class;
+		}
 	}
 }