Consistent exception naming across InvocableHandlerMethod variants

See gh-22900

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/InvocableHandlerMethod.java

 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -147,11 +147,11 @@ public class InvocableHandlerMethod extends HandlerMethod {
 				args[i] = this.resolvers.resolveArgument(parameter, message);
 			}
 			catch (Exception ex) {
-				// Leave stack trace for later, exception may actually be resolved and handled..
+				// Leave stack trace for later, exception may actually be resolved and handled...
 				if (logger.isDebugEnabled()) {
-					String error = ex.getMessage();
-					if (error != null && !error.contains(parameter.getExecutable().toGenericString())) {
-						logger.debug(formatArgumentError(parameter, error));
+					String exMsg = ex.getMessage();
+					if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
+						logger.debug(formatArgumentError(parameter, exMsg));
 					}
 				}
 				throw ex;

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

 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -166,11 +166,11 @@ public class InvocableHandlerMethod extends HandlerMethod {
 				args[i] = this.resolvers.resolveArgument(parameter, mavContainer, request, this.dataBinderFactory);
 			}
 			catch (Exception ex) {
-				// Leave stack trace for later, exception may actually be resolved and handled..
+				// Leave stack trace for later, exception may actually be resolved and handled...
 				if (logger.isDebugEnabled()) {
-					String error = ex.getMessage();
-					if (error != null && !error.contains(parameter.getExecutable().toGenericString())) {
-						logger.debug(formatArgumentError(parameter, error));
+					String exMsg = ex.getMessage();
+					if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
+						logger.debug(formatArgumentError(parameter, exMsg));
 					}
 				}
 				throw ex;

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/InvocableHandlerMethod.java

 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -190,7 +190,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 			try {
 				argMonos.add(this.resolvers.resolveArgument(parameter, bindingContext, exchange)
 						.defaultIfEmpty(NO_ARG_VALUE)
-						.doOnError(cause -> logArgumentErrorIfNecessary(exchange, parameter, cause)));
+						.doOnError(ex -> logArgumentErrorIfNecessary(exchange, parameter, ex)));
 			}
 			catch (Exception ex) {
 				logArgumentErrorIfNecessary(exchange, parameter, ex);
@@ -201,14 +201,12 @@ public class InvocableHandlerMethod extends HandlerMethod {
 				Stream.of(values).map(o -> o != NO_ARG_VALUE ? o : null).toArray());
 	}
 
-	private void logArgumentErrorIfNecessary(
-			ServerWebExchange exchange, MethodParameter parameter, Throwable cause) {
-
-		// Leave stack trace for later, if error is not handled..
-		String message = cause.getMessage();
-		if (!message.contains(parameter.getExecutable().toGenericString())) {
+	private void logArgumentErrorIfNecessary(ServerWebExchange exchange, MethodParameter parameter, Throwable ex) {
+		// Leave stack trace for later, if error is not handled...
+		String exMsg = ex.getMessage();
+		if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
 			if (logger.isDebugEnabled()) {
-				logger.debug(exchange.getLogPrefix() + formatArgumentError(parameter, message));
+				logger.debug(exchange.getLogPrefix() + formatArgumentError(parameter, exMsg));
 			}
 		}
 	}