From b94b0731ef5acdd3b5cf4a6277aeb9563be4b472 Mon Sep 17 00:00:00 2001
From: markt <markt@13f79535-47bb-0310-9956-ffa450edef68>
Date: Fri, 1 Jul 2011 14:15:48 +0000
Subject: [PATCH] Fix possible NPE when serving STM servlets

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1141948 13f79535-47bb-0310-9956-ffa450edef68
---
 java/org/apache/catalina/core/StandardWrapper.java | 7 ++++---
 webapps/docs/changelog.xml                         | 4 ++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/java/org/apache/catalina/core/StandardWrapper.java b/java/org/apache/catalina/core/StandardWrapper.java
index ba2b2feb2..95d857fb8 100644
--- a/java/org/apache/catalina/core/StandardWrapper.java
+++ b/java/org/apache/catalina/core/StandardWrapper.java
@@ -1115,10 +1115,11 @@ public class StandardWrapper extends ContainerBase
 
             classLoadTime=(int) (System.currentTimeMillis() -t1);
 
-            singleThreadModel = servlet instanceof SingleThreadModel;
-            if (singleThreadModel) {
-                if (instancePool == null)
+            if (servlet instanceof SingleThreadModel) {
+                if (instancePool == null) {
                     instancePool = new Stack<Servlet>();
+                }
+                singleThreadModel = true;
             }
 
             initServlet(servlet);
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 7ad533db2..140870632 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -186,6 +186,10 @@
         support (enhancement <bug>12428</bug>) that could trigger authentication
         even if preemptive authentication was disabled. (markt) 
       </fix>
+      <fix>
+        Prevent possible NPE when serving Servlets that implement the
+        SingleThreadModel interface. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Coyote">
-- 
2.11.0