From bc416fc23d32536d94c0fe5f53db6e3879bbc3ad Mon Sep 17 00:00:00 2001
From: markt <markt@13f79535-47bb-0310-9956-ffa450edef68>
Date: Wed, 10 Aug 2011 13:22:52 +0000
Subject: [PATCH] Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=51640
 Improve memory leak protection for DriverManager

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1156171 13f79535-47bb-0310-9956-ffa450edef68
---
 .../core/JreMemoryLeakPreventionListener.java      | 29 +++++++++++++++++++---
 webapps/docs/config/listeners.xml                  |  8 ++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java b/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
index e646c8f39..91d11d2d0 100644
--- a/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
+++ b/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
@@ -23,6 +23,7 @@ import java.lang.reflect.Method;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLConnection;
+import java.sql.DriverManager;
 
 import javax.imageio.ImageIO;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -150,8 +151,8 @@ public class JreMemoryLeakPreventionListener implements LifecycleListener {
     }
     
     /**
-     * <code>com.sun.jndi.ldap.LdapPoolManager</code> class spawns a thread when it
-     * is initialized if the system property
+     * <code>com.sun.jndi.ldap.LdapPoolManager</code> class spawns a thread when
+     * it is initialized if the system property
      * <code>com.sun.jndi.ldap.connect.pool.timeout</code> is greater than 0.
      * That thread inherits the context class loader of the current thread, so
      * that there may be a web application class loader leak if the web app
@@ -162,7 +163,21 @@ public class JreMemoryLeakPreventionListener implements LifecycleListener {
     public void setLdapPoolProtection(boolean ldapPoolProtection) {
         this.ldapPoolProtection = ldapPoolProtection;
     }
-    
+
+    /**
+     * The first access to {@link DriverManager} will trigger the loading of
+     * all {@link java.sql.Driver}s in the the current class loader. The web
+     * application level memory leak protection can take care of this in most
+     * cases but triggering the loading here has fewer side-effects. 
+     */
+    private boolean driverManagerProtection = true;
+    public boolean isDriverManagerProtection() {
+        return driverManagerProtection;
+    }
+    public void setDriverManagerProtection(boolean driverManagerProtection) {
+        this.driverManagerProtection = driverManagerProtection;
+    }
+
     @Override
     public void lifecycleEvent(LifecycleEvent event) {
         // Initialise these classes when Tomcat starts
@@ -178,6 +193,14 @@ public class JreMemoryLeakPreventionListener implements LifecycleListener {
                         ClassLoader.getSystemClassLoader());
 
                 /*
+                 * First call to this loads all drivers in the current class
+                 * loader
+                 */
+                if (driverManagerProtection) {
+                    DriverManager.getDrivers();
+                }
+
+                /*
                  * Several components end up calling:
                  * sun.awt.AppContext.getAppContext()
                  * 
diff --git a/webapps/docs/config/listeners.xml b/webapps/docs/config/listeners.xml
index 8b50f6147..207a5f150 100644
--- a/webapps/docs/config/listeners.xml
+++ b/webapps/docs/config/listeners.xml
@@ -174,6 +174,14 @@
         is <code>true</code>.</p>
       </attribute>
 
+      <attribute name="driverManagerProtection" required="false">
+        <p>The first use of <code>java.sql.DriverManager</code> will trigger the
+        loading of JDBNC Driver in the the current class loader. The web
+        application level memory leak protection can take care of this in most
+        cases but triggering the loading here has fewer side-effects. The
+        default is <code>true</code></p>
+      </attribute>
+
       <attribute name="gcDaemonProtection" required="false">
         <p>Enables protection so that calls to
         <code>sun.misc.GC.requestLatency(long)</code> triggered by a web
-- 
2.11.0