Apache Tomcat 7.x will now longer log a warning when unloading the web…

Apache Tomcat 7.x will now longer log a warning when unloading the web application, if using a connection pool.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,8 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>H2 Console: support the Midori browser (for Debian / Raspberry Pi)
+<ul><li>Apache Tomcat 7.x will now longer log a warning when unloading the web application, if using a connection pool.
+</li><li>H2 Console: support the Midori browser (for Debian / Raspberry Pi)
 </li><li>When opening a remote session, don't open a temporary file if the trace level is set to zero
 </li></ul>
 

h2/src/main/org/h2/Driver.java

@@ -180,4 +180,21 @@ public class Driver implements java.sql.Driver {
         DEFAULT_CONNECTION.set(c);
     }
 
+    /**
+     * INTERNAL
+     */
+    public static void setThreadContextClassLoader(Thread thread) {
+        // Apache Tomcat: use the classloader of the driver to avoid the
+        // following log message:
+        // org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
+        // SEVERE: The web application appears to have started a thread named
+        // ... but has failed to stop it.
+        // This is very likely to create a memory leak.
+        try {
+            thread.setContextClassLoader(Driver.class.getClassLoader());
+        } catch (Throwable t) {
+            // ignore
+        }
+    }
+
 }

h2/src/main/org/h2/store/FileLock.java

@@ -15,6 +15,7 @@ import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.UnknownHostException;
 import java.util.Properties;
+import org.h2.Driver;
 import org.h2.constant.ErrorCode;
 import org.h2.engine.Constants;
 import org.h2.engine.SessionRemote;
@@ -347,6 +348,7 @@ public class FileLock implements Runnable {
             throw getExceptionFatal("Concurrent update", null);
         }
         watchdog = new Thread(this, "H2 File Lock Watchdog " + fileName);
+        Driver.setThreadContextClassLoader(watchdog);
         watchdog.setDaemon(true);
         watchdog.setPriority(Thread.MAX_PRIORITY - 1);
         watchdog.start();

h2/src/main/org/h2/store/WriterThread.java

@@ -8,6 +8,7 @@ package org.h2.store;
 
 import java.lang.ref.WeakReference;
 import java.security.AccessControlException;
+import org.h2.Driver;
 import org.h2.engine.Constants;
 import org.h2.engine.Database;
 import org.h2.message.Trace;
@@ -61,6 +62,7 @@ public class WriterThread implements Runnable {
         try {
             WriterThread writer = new WriterThread(database, writeDelay);
             writer.thread = new Thread(writer, "H2 Log Writer " + database.getShortName());
+            Driver.setThreadContextClassLoader(writer.thread);
             writer.thread.setDaemon(true);
             return writer;
         } catch (AccessControlException e) {