diff --git a/vraptor-core/src/main/java/br/com/caelum/vraptor/VRaptor.java b/vraptor-core/src/main/java/br/com/caelum/vraptor/VRaptor.java
index bb3374b72..dd0376da2 100644
--- a/vraptor-core/src/main/java/br/com/caelum/vraptor/VRaptor.java
+++ b/vraptor-core/src/main/java/br/com/caelum/vraptor/VRaptor.java
@@ -183,7 +183,8 @@ private void validateIfCdiIsFound() throws ServletException {
 	 * 5. The request MUST contain an |Upgrade| header field whose value MUST include the "websocket" keyword.
 	 */
 	private boolean isWebsocketRequest(HttpServletRequest request) {
-		return request.getHeader("Upgrade") != null && request.getHeader("Upgrade").toLowerCase().contains("websocket");
+		String upgradeHeader = request.getHeader("Upgrade");
+		return upgradeHeader != null && upgradeHeader.toLowerCase().contains("websocket");
 	}
 	
 }