Fix Javadoc warnings

Fixes gh-347

spring-session/build.gradle

@@ -63,7 +63,6 @@ ext.javadocLinks = [
 		"http://tiles.apache.org/framework/apidocs/",
 		"http://aopalliance.sourceforge.net/doc/",
 		"http://www.eclipse.org/aspectj/doc/released/aspectj5rt-api/",
-		"http://ehcache.org/apidocs/",
 		"http://quartz-scheduler.org/api/2.2.0/",
 		"http://fasterxml.github.com/jackson-core/javadoc/2.3.0/",
 		"http://fasterxml.github.com/jackson-databind/javadoc/2.3.0/",

spring-session/src/main/java/org/springframework/session/data/redis/RedisOperationsSessionRepository.java

@@ -552,7 +552,7 @@ public class RedisOperationsSessionRepository implements FindByPrincipalNameSess
 	/**
 	 * Gets the prefix for the channel that SessionCreatedEvent are published to. The suffix is the session id of the session that was created.
 	 *
-	 * @return
+	 * @return the prefix for the channel that SessionCreatedEvent are published to
 	 */
 	public String getSessionCreatedChannelPrefix() {
 		return this.keyPrefix + "event:created:";

spring-session/src/main/java/org/springframework/session/data/redis/config/annotation/web/http/EnableRedisHttpSession.java

@@ -73,7 +73,7 @@ public @interface EnableRedisHttpSession {
 	 * same Redis instance.
 	 * </p>
 	 *
-	 * @return
+	 * @return the unique namespace for keys
 	 */
 	String redisNamespace() default "";
 }

spring-session/src/main/java/org/springframework/session/events/AbstractSessionEvent.java

@@ -49,6 +49,7 @@ public abstract class AbstractSessionEvent extends ApplicationEvent {
 	 * {@link SessionRepository} implementations it may not be possible to get
 	 * the original session in which case this may be null.
 	 *
+	 * @param <S> The type of Session
 	 * @return the expired {@link Session} or null if the data store does not support obtaining it
 	 */
 	@SuppressWarnings("unchecked")

spring-session/src/main/java/org/springframework/session/events/SessionCreatedEvent.java

@@ -35,8 +35,8 @@ public class SessionCreatedEvent extends AbstractSessionEvent {
 	}
 
 	/**
-	 * @param source
-	 * @param session
+	 * @param source The Source of the SessionCreatedEvent
+	 * @param session the Session that was created
 	 */
 	public SessionCreatedEvent(Object source, Session session) {
 		super(source, session);

spring-session/src/main/java/org/springframework/session/events/SessionDestroyedEvent.java

@@ -32,8 +32,8 @@ public class SessionDestroyedEvent extends AbstractSessionEvent {
 	}
 
 	/**
-	 * @param source
-	 * @param session
+	 * @param source The Source of the SessionDestoryedEvent
+	 * @param session the Session that was created
 	 */
 	public SessionDestroyedEvent(Object source, Session session) {
 		super(source, session);

spring-session/src/main/java/org/springframework/session/web/http/HttpSessionManager.java

@@ -66,7 +66,7 @@ public interface HttpSessionManager {
 	 * </code>
 	 *
 	 * @param request the {@link HttpServletRequest} to get a new alias from
-	 * @return
+	 * @return Gets a new and unique Session alias.
 	 */
 	String getNewSessionAlias(HttpServletRequest request);
 }

spring-session/src/main/java/org/springframework/session/web/http/OncePerRequestFilter.java

@@ -71,12 +71,17 @@ abstract class OncePerRequestFilter implements Filter {
 		}
 	}
 
-
 	/**
 	 * Same contract as for {@code doFilter}, but guaranteed to be
 	 * just invoked once per request within a single request thread.
 	 * <p>Provides HttpServletRequest and HttpServletResponse arguments instead of the
 	 * default ServletRequest and ServletResponse ones.
+	 *
+	 * @param request the request
+	 * @param response the response
+	 * @param filterChain the FilterChain
+	 * @throws ServletException thrown when a non-I/O exception has occurred
+	 * @throws IOException thrown when an I/O exception of some sort has occurred
 	 * @see Filter#doFilter
 	 */
 	protected abstract void doFilterInternal(