Fix [serial] compiler warnings

Fix serialization warnings by applying @SuppressWarnings("serial")
when appropriate.

In certain cases and for unknown reasons, a correctly-placed
@SuppressWarnings("serial") annotation will fix the warning at the
javac level (i.e. the Gradle command-line), but will produce an
"unnecessary @SuppressWarnings" warning within Eclipse. In these
cases, a private static final serialVersionUID field has been added
with the default value of 1L.

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/ModelAndViewDefiningException.java

@@ -30,6 +30,7 @@ import javax.portlet.PortletException;
  * @author Juergen Hoeller
  * @since 2.0
  */
+@SuppressWarnings("serial")
 public class ModelAndViewDefiningException extends PortletException {
 
 	private ModelAndView modelAndView;

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/NoHandlerFoundException.java

@@ -28,6 +28,7 @@ import org.springframework.core.style.StylerUtils;
  * @author Juergen Hoeller
  * @since 3.0.5
  */
+@SuppressWarnings("serial")
 public class NoHandlerFoundException extends PortletException {
 
 	/**

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/bind/MissingPortletRequestParameterException.java

@@ -22,6 +22,7 @@ package org.springframework.web.portlet.bind;
  * @author Juergen Hoeller
  * @since 2.0.2
  */
+@SuppressWarnings("serial")
 public class MissingPortletRequestParameterException extends PortletRequestBindingException {
 
 	private final String parameterName;

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/bind/PortletRequestBindingException.java

@@ -26,6 +26,7 @@ import javax.portlet.PortletException;
  * @author John A. Lewis
  * @since 2.0
  */
+@SuppressWarnings("serial")
 public class PortletRequestBindingException extends PortletException {
 
 	/**

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/bind/PortletRequestParameterPropertyValues.java

@@ -37,6 +37,7 @@ import org.springframework.web.portlet.util.PortletUtils;
  * @since 2.0
  * @see org.springframework.web.portlet.util.PortletUtils#getParametersStartingWith
  */
+@SuppressWarnings("serial")
 public class PortletRequestParameterPropertyValues extends MutablePropertyValues {
 
 	/** Default prefix separator */

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/context/PortletApplicationContextUtils.java

@@ -241,6 +241,7 @@ public abstract class PortletApplicationContextUtils {
 	/**
 	 * Factory that exposes the current request object on demand.
 	 */
+	@SuppressWarnings("serial")
 	private static class RequestObjectFactory implements ObjectFactory<PortletRequest>, Serializable {
 
 		public PortletRequest getObject() {
@@ -257,6 +258,7 @@ public abstract class PortletApplicationContextUtils {
 	/**
 	 * Factory that exposes the current session object on demand.
 	 */
+	@SuppressWarnings("serial")
 	private static class SessionObjectFactory implements ObjectFactory<PortletSession>, Serializable {
 
 		public PortletSession getObject() {
@@ -273,6 +275,7 @@ public abstract class PortletApplicationContextUtils {
 	/**
 	 * Factory that exposes the current WebRequest object on demand.
 	 */
+	@SuppressWarnings("serial")
 	private static class WebRequestObjectFactory implements ObjectFactory<WebRequest>, Serializable {
 
 		public WebRequest getObject() {

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/context/PortletRequestHandledEvent.java

@@ -28,6 +28,7 @@ import org.springframework.web.context.support.RequestHandledEvent;
  * @see org.springframework.web.portlet.FrameworkPortlet
  * @see org.springframework.context.ApplicationContext#publishEvent
  */
+@SuppressWarnings("serial")
 public class PortletRequestHandledEvent extends RequestHandledEvent {
 
 	/** Name of the portlet that handled the request */

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/handler/PortletRequestMethodNotSupportedException.java

@@ -27,6 +27,7 @@ import org.springframework.util.StringUtils;
  * @author Juergen Hoeller
  * @since 3.0
  */
+@SuppressWarnings("serial")
 public class PortletRequestMethodNotSupportedException extends PortletException {
 
 	private String method;
@@ -78,4 +79,4 @@ public class PortletRequestMethodNotSupportedException extends PortletException
 		return this.supportedMethods;
 	}
 
-}
+}

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/handler/PortletSessionRequiredException.java

@@ -25,6 +25,7 @@ import javax.portlet.PortletException;
  * @since 2.0
  * @see org.springframework.web.portlet.handler.PortletContentGenerator
  */
+@SuppressWarnings("serial")
 public class PortletSessionRequiredException extends PortletException {
 
 	/**