Prevent StackOverflowError in AbstractJackson2HttpMessageConverter

Issue: SPR-14520

spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java

@@ -356,9 +356,13 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 				return resolvedType;
 			}
 		}
-		resolvedType = resolveVariable(typeVariable, contextType.getSuperType());
-		if (resolvedType.resolve() != null) {
-			return resolvedType;
+
+		ResolvableType superType = contextType.getSuperType();
+		if (superType != ResolvableType.NONE) {
+			resolvedType = resolveVariable(typeVariable, superType);
+			if (resolvedType.resolve() != null) {
+				return resolvedType;
+			}
 		}
 		for (ResolvableType ifc : contextType.getInterfaces()) {
 			resolvedType = resolveVariable(typeVariable, ifc);

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java

@@ -692,6 +692,25 @@ public class RequestResponseBodyMethodProcessorTests {
 		assertEquals("UTF-8", this.servletResponse.getCharacterEncoding());
 	}
 
+	@Test  // SPR-14520
+	public void resolveArgumentTypeVariableWithGenericInterface() throws Exception {
+		this.servletRequest.setContent("\"foo\"".getBytes("UTF-8"));
+		this.servletRequest.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);
+
+		Method method = MyControllerImplementingInterface.class.getMethod("handle", Object.class);
+		HandlerMethod handlerMethod = new HandlerMethod(new MyControllerImplementingInterface(), method);
+		MethodParameter methodParameter = handlerMethod.getMethodParameters()[0];
+
+		List<HttpMessageConverter<?>> converters = new ArrayList<>();
+		converters.add(new MappingJackson2HttpMessageConverter());
+
+		RequestResponseBodyMethodProcessor processor = new RequestResponseBodyMethodProcessor(converters);
+
+		String value = (String)processor.readWithMessageConverters(this.request, methodParameter,
+				methodParameter.getGenericParameterType());
+		assertEquals("foo", value);
+	}
+
 	private void assertContentDisposition(RequestResponseBodyMethodProcessor processor,
 			boolean expectContentDisposition, String requestURI, String comment) throws Exception {
 
@@ -1011,4 +1030,13 @@ public class RequestResponseBodyMethodProcessorTests {
 		}
 	}
 
+	interface MappingInterface<A> {
+		default A handle(@RequestBody A arg) {
+			return arg;
+		}
+	}
+
+	static class MyControllerImplementingInterface implements MappingInterface<String> {
+	}
+
 }