Fix NPE in InvocableHandlerMethod

Issue: SPR-13917
(cherry picked from commit b1a46cc)

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/method/support/InvocableHandlerMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,15 +32,15 @@
 import org.springframework.web.method.HandlerMethod;
 
 /**
- * Provides a method for invoking the handler method for a given request after resolving its method argument
- * values through registered {@link HandlerMethodArgumentResolver}s.
+ * Provides a method for invoking the handler method for a given request after resolving its
+ * method argument values through registered {@link HandlerMethodArgumentResolver}s.
  *
- * <p>Argument resolution often requires a {@link WebDataBinder} for data binding or for type conversion.
- * Use the {@link #setDataBinderFactory(WebDataBinderFactory)} property to supply a binder factory to pass to
- * argument resolvers.
+ * <p>Argument resolution often requires a {@link WebDataBinder} for data binding or for type
+ * conversion. Use the {@link #setDataBinderFactory(WebDataBinderFactory)} property to supply
+ * a binder factory to pass to argument resolvers.
  *
- * <p>Use {@link #setHandlerMethodArgumentResolvers(HandlerMethodArgumentResolverComposite)} to customize
- * the list of argument resolvers.
+ * <p>Use {@link #setHandlerMethodArgumentResolvers(HandlerMethodArgumentResolverComposite)}
+ * to customize the list of argument resolvers.
  *
  * @author Rossen Stoyanchev
  * @since 3.1
@@ -55,17 +55,17 @@ public class InvocableHandlerMethod extends HandlerMethod {
 
 
 	/**
-	 * Create an instance from the given handler and method.
+	 * Create an instance from a {@code HandlerMethod}.
 	 */
-	public InvocableHandlerMethod(Object bean, Method method) {
-		super(bean, method);
+	public InvocableHandlerMethod(HandlerMethod handlerMethod) {
+		super(handlerMethod);
 	}
 
 	/**
-	 * Create an instance from a {@code HandlerMethod}.
+	 * Create an instance from a bean instance and a method.
 	 */
-	public InvocableHandlerMethod(HandlerMethod handlerMethod) {
-		super(handlerMethod);
+	public InvocableHandlerMethod(Object bean, Method method) {
+		super(bean, method);
 	}
 
 	/**
@@ -75,7 +75,9 @@ public InvocableHandlerMethod(HandlerMethod handlerMethod) {
 	 * @param parameterTypes the method parameter types
 	 * @throws NoSuchMethodException when the method cannot be found
 	 */
-	public InvocableHandlerMethod(Object bean, String methodName, Class<?>... parameterTypes) throws NoSuchMethodException {
+	public InvocableHandlerMethod(Object bean, String methodName, Class<?>... parameterTypes)
+			throws NoSuchMethodException {
+
 		super(bean, methodName, parameterTypes);
 	}
 
@@ -107,16 +109,18 @@ public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDisc
 
 
 	/**
-	 * Invoke the method after resolving its argument values in the context of the given request. <p>Argument
-	 * values are commonly resolved through {@link HandlerMethodArgumentResolver}s. The {@code provideArgs}
-	 * parameter however may supply argument values to be used directly, i.e. without argument resolution.
-	 * Examples of provided argument values include a {@link WebDataBinder}, a {@link SessionStatus}, or
-	 * a thrown exception instance. Provided argument values are checked before argument resolvers.
+	 * Invoke the method after resolving its argument values in the context of the given request.
+	 * <p>Argument values are commonly resolved through {@link HandlerMethodArgumentResolver}s.
+	 * The {@code providedArgs} parameter however may supply argument values to be used directly,
+	 * i.e. without argument resolution. Examples of provided argument values include a
+	 * {@link WebDataBinder}, a {@link SessionStatus}, or a thrown exception instance.
+	 * Provided argument values are checked before argument resolvers.
 	 * @param request the current request
 	 * @param mavContainer the ModelAndViewContainer for this request
 	 * @param providedArgs "given" arguments matched by type, not resolved
 	 * @return the raw value returned by the invoked method
-	 * @exception Exception raised if no suitable argument resolver can be found, or the method raised an exception
+	 * @exception Exception raised if no suitable argument resolver can be found,
+	 * or if the method raised an exception
 	 */
 	public final Object invokeForRequest(NativeWebRequest request, ModelAndViewContainer mavContainer,
 			Object... providedArgs) throws Exception {
@@ -129,7 +133,7 @@ public final Object invokeForRequest(NativeWebRequest request, ModelAndViewConta
 			sb.append(Arrays.asList(args));
 			logger.trace(sb.toString());
 		}
-		Object returnValue = invoke(args);
+		Object returnValue = doInvoke(args);
 		if (logger.isTraceEnabled()) {
 			logger.trace("Method [" + getMethod().getName() + "] returned [" + returnValue + "]");
 		}
@@ -159,8 +163,8 @@ private Object[] getMethodArgumentValues(NativeWebRequest request, ModelAndViewC
 					continue;
 				}
 				catch (Exception ex) {
-					if (logger.isTraceEnabled()) {
-						logger.trace(getArgumentResolutionErrorMessage("Error resolving argument", i), ex);
+					if (logger.isDebugEnabled()) {
+						logger.debug(getArgumentResolutionErrorMessage("Error resolving argument", i), ex);
 					}
 					throw ex;
 				}
@@ -180,7 +184,8 @@ private String getArgumentResolutionErrorMessage(String message, int index) {
 	}
 
 	/**
-	 * Adds HandlerMethod details such as the controller type and method signature to the given error message.
+	 * Adds HandlerMethod details such as the controller type and method
+	 * signature to the given error message.
 	 * @param message error message to append the HandlerMethod details to
 	 */
 	protected String getDetailedErrorMessage(String message) {
@@ -206,17 +211,19 @@ private Object resolveProvidedArgument(MethodParameter parameter, Object... prov
 		return null;
 	}
 
+
 	/**
 	 * Invoke the handler method with the given argument values.
 	 */
-	private Object invoke(Object... args) throws Exception {
+	protected Object doInvoke(Object... args) throws Exception {
 		ReflectionUtils.makeAccessible(getBridgedMethod());
 		try {
 			return getBridgedMethod().invoke(getBean(), args);
 		}
 		catch (IllegalArgumentException ex) {
 			assertTargetBean(getBridgedMethod(), getBean(), args);
-			throw new IllegalStateException(getInvocationErrorMessage(ex.getMessage(), args), ex);
+			String message = (ex.getMessage() != null ? ex.getMessage() : "Illegal argument");
+			throw new IllegalStateException(getInvocationErrorMessage(message, args), ex);
 		}
 		catch (InvocationTargetException ex) {
 			// Unwrap for HandlerExceptionResolvers ...
@@ -249,7 +256,7 @@ private void assertTargetBean(Method method, Object targetBean, Object[] args) {
 		Class<?> targetBeanClass = targetBean.getClass();
 		if (!methodDeclaringClass.isAssignableFrom(targetBeanClass)) {
 			String msg = "The mapped controller method class '" + methodDeclaringClass.getName() +
-					"' is not an instance of the actual controller bean instance '" +
+					"' is not an instance of the actual controller bean class '" +
 					targetBeanClass.getName() + "'. If the controller requires proxying " +
 					"(e.g. due to @Transactional), please use class-based proxying.";
 			throw new IllegalStateException(getInvocationErrorMessage(msg, args));
@@ -259,7 +266,7 @@ private void assertTargetBean(Method method, Object targetBean, Object[] args) {
 	private String getInvocationErrorMessage(String message, Object[] resolvedArgs) {
 		StringBuilder sb = new StringBuilder(getDetailedErrorMessage(message));
 		sb.append("Resolved arguments: \n");
-		for (int i=0; i < resolvedArgs.length; i++) {
+		for (int i = 0; i < resolvedArgs.length; i++) {
 			sb.append("[").append(i).append("] ");
 			if (resolvedArgs[i] == null) {
 				sb.append("[null] \n");

spring-web/src/test/java/org/springframework/web/method/support/InvocableHandlerMethodTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,16 +16,11 @@
 
 package org.springframework.web.method.support;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
 import java.lang.reflect.Method;
 
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.core.MethodParameter;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.mock.web.test.MockHttpServletRequest;
@@ -34,6 +29,9 @@
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.ServletWebRequest;
 
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
 /**
  * Test fixture for {@link InvocableHandlerMethod} unit tests.
  *
@@ -198,6 +196,26 @@ public void invocationTargetException() throws Exception {
 		}
 	}
 
+	@Test  // SPR-13917
+	public void invocationErrorMessage() throws Exception {
+		HandlerMethodArgumentResolverComposite composite = new HandlerMethodArgumentResolverComposite();
+		composite.addResolver(new StubArgumentResolver(double.class, null));
+
+		Method method = Handler.class.getDeclaredMethod("handle", double.class);
+		Object handler = new Handler();
+		InvocableHandlerMethod hm = new InvocableHandlerMethod(handler, method);
+		hm.setHandlerMethodArgumentResolvers(composite);
+
+		try {
+			hm.invokeForRequest(this.webRequest, new ModelAndViewContainer());
+			fail();
+		}
+		catch (IllegalStateException ex) {
+			assertThat(ex.getMessage(), containsString("Illegal argument"));
+		}
+	}
+
+
 	private void invokeExceptionRaisingHandler(Throwable expected) throws Exception {
 		Method method = ExceptionRaisingHandler.class.getDeclaredMethod("raiseException");
 		Object handler = new ExceptionRaisingHandler(expected);
@@ -212,6 +230,9 @@ private static class Handler {
 		public String handle(Integer intArg, String stringArg) {
 			return intArg + "-" + stringArg;
 		}
+
+		public void handle(double amount) {
+		}
 	}