Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=49414

Try to differentiate between request threads and threads started by applications

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@957830 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/java/org/apache/catalina/loader/LocalStrings.properties b/java/org/apache/catalina/loader/LocalStrings.properties
index 3d02dbe..18c1a08 100644 (file)
--- a/java/org/apache/catalina/loader/LocalStrings.properties
+++ b/java/org/apache/catalina/loader/LocalStrings.properties
@@ -46,7 +46,8 @@ webappClassLoader.clearThreadLocalFail=Failed to clear ThreadLocal references fo
 webappClassLoader.stopThreadFail=Failed to terminate thread named [{0}] for web application [{1}]
 webappClassLoader.stopTimerThreadFail=Failed to terminate TimerThread named [{0}] for web application [{1}]
 webappClassLoader.validationErrorJarPath=Unable to validate JAR entry with name {0}
-webappClassLoader.warnThread=The web application [{0}] appears to have started a thread named [{1}] but has failed to stop it. This is very likely to create a memory leak. 
+webappClassLoader.warnRequestThread=The web application [{0}] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation.
+webappClassLoader.warnThread=The web application [{0}] appears to have started a thread named [{1}] but has failed to stop it. This is very likely to create a memory leak.
 webappClassLoader.warnTimerThread=The web application [{0}] appears to have started a TimerThread named [{1}] via the java.util.Timer API but has failed to stop it. To prevent a memory leak, the timer (and hence the associated thread) has been forcibly canceled. 
 webappClassLoader.wrongVersion=(unable to load class {0})
 webappLoader.addRepository=Adding repository {0}

diff --git a/java/org/apache/catalina/loader/WebappClassLoader.java b/java/org/apache/catalina/loader/WebappClassLoader.java
index ccd9205..13e419b 100644 (file)
--- a/java/org/apache/catalina/loader/WebappClassLoader.java
+++ b/java/org/apache/catalina/loader/WebappClassLoader.java
@@ -2184,8 +2184,13 @@ public class WebappClassLoader
                         continue;
                     }
 
-                    log.error(sm.getString("webappClassLoader.warnThread",
-                            contextName, thread.getName()));
+                    if (isRequestThread(thread)) {
+                        log.error(sm.getString("webappClassLoader.warnRequestThread",
+                                contextName, thread.getName()));
+                    } else {
+                        log.error(sm.getString("webappClassLoader.warnThread",
+                                contextName, thread.getName()));
+                    }
                     
                     // Don't try an stop the threads unless explicitly
                     // configured to do so
@@ -2241,6 +2246,36 @@ public class WebappClassLoader
     }
 
     
+    /*
+     * Look at a threads stack trace to see if it is a request thread or not. It
+     * isn't perfect, but it should be good-enough for most cases.
+     */
+    private boolean isRequestThread(Thread thread) {
+        
+        StackTraceElement[] elements = thread.getStackTrace();
+        
+        if (elements == null || elements.length == 0) {
+            // Must have stopped already. Too late to ignore it. Assume not a
+            // request processing thread.
+            return false;
+        }
+        
+        // Step through the methods in reverse order looking for a
+        // CoyoteAdapter.service() call. All requests will have this unless
+        // Tomcat has been heavily modified - in which case there isn't much we
+        // can do.
+        for (int i = 0; i < elements.length; i++) {
+            StackTraceElement element = elements[elements.length - (i+1)];
+            if ("org.apache.catalina.connector.CoyoteAdapter".equals(
+                    element.getClassName()) &&
+                    "service".equals(element.getMethodName())) {
+                return true;
+            }
+        }
+        return false;
+    }
+    
+    
     private void clearReferencesStopTimerThread(Thread thread) {
         
         // Need to get references to:

diff --git a/webapps/docs/config/context.xml b/webapps/docs/config/context.xml
index 729e033..302e926 100644 (file)
--- a/webapps/docs/config/context.xml
+++ b/webapps/docs/config/context.xml
@@ -465,9 +465,8 @@
       </attribute>
 
       <attribute name="unloadDelay" required="false">
-        <p>Amount of ms that the container will wait for servlets to unload.
-        If not specified, the default value of the flag is <code>2000</code> 
-        ms.</p>
+        <p>Number of ms that the container will wait for servlets to unload.
+        If not specified, the default value is <code>2000</code> ms.</p>
       </attribute>
 
       <attribute name="unpackWAR" required="false">