Tomcat Windows service shutdown got SEVERE error NullPointerException

Posted on 2004-10-29
Last Modified: 2009-07-29

I have a service created for Windows using jk_nt_service.exe.  It is an application that launches Tomcat server and a few webapps.  The service starts up okay, but when I stop it, I got the following SEVERE error.

Oct 29, 2004 11:18:21 AM org.apache.tomcat.util.threads.ThreadPool$ControlRunnable run
SEVERE: Caught exception (java.lang.NullPointerException) executing org.apache.jk.common.SocketConnection@cb800f, terminating thread

There are no other log or stack trace.  Could you let me know what may be the problems or how I go about to debug this?  We have a wrapper that wraps and launches Tomcat.  Where should I look/debug to find the problem?  Thanks.  Below are excerpt from my and serverl.xml file for shutdown port and AJP protocol:

# The NT service uses AJP12/AJP13 to shutdown Tomcat. The
# wrapper.shutdown_port tells the service the identity of the port that
# is used by AJP12/AJP13.

# Can either be ajp12 or ajp13 depending on your configuration.
# Default value is ajp12

    <!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
    <Connector port="8009"
               enableLookups="false" redirectPort="8443" debug="1"
               protocol="AJP/1.3" />
Question by:tlchu

    Expert Comment

    If you are running on windows just go to taskmanager to shutdown a service ,select a a service java* and end process and than try to start tomcat.

    Author Comment


    Getting rid of the service is not a problem.  The problem is I have some cleanup to do during shutdown.  I believe this error keeps the cleanup code from being executed.  I need to find out the root of this problem and get it to shutdown cleanly.
    LVL 23

    Expert Comment


    Look at the example below and setup the parameters as described...


    <!-- Example Server Configuration File -->
    <!-- Note that component elements are nested corresponding to their
         parent-child relationships with each other -->

    <!-- A "Server" is a singleton element that represents the entire JVM,
         which may contain one or more "Service" instances.  The Server
         listens for a shutdown command on the indicated port.

         Note:  A "Server" is not itself a "Container", so you may not
         define subcomponents such as "Valves" or "Loggers" at this level.

    <Server port="8005" shutdown="SHUTDOWN" debug="0">

      <!-- Comment these entries out to disable JMX MBeans support -->
      <!-- You may also configure custom components (e.g. Valves/Realms) by
           including your own mbean-descriptor file(s), and setting the
           "descriptors" attribute to point to a ';' seperated list of paths
           (in the ClassLoader sense) of files to add to the default list.
           e.g. descriptors="/com/myfirm/mypackage/mbean-descriptor.xml"
      <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener"
      <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"

      <!-- Global JNDI resources -->

        <!-- Test entry for demonstration purposes -->
        <Environment name="simpleValue" type="java.lang.Integer" value="30"/>

        <!-- Editable user database that can also be used by
             UserDatabaseRealm to authenticate users -->
        <Resource name="UserDatabase" auth="Container"
           description="User database that can be updated and saved">
        <ResourceParams name="UserDatabase">


      <!-- A "Service" is a collection of one or more "Connectors" that share
           a single "Container" (and therefore the web applications visible
           within that Container).  Normally, that Container is an "Engine",
           but this is not required.

           Note:  A "Service" is not itself a "Container", so you may not
           define subcomponents such as "Valves" or "Loggers" at this level.

      <!-- Define the Tomcat Stand-Alone Service -->
      <Service name="Tomcat-Standalone">

        <!-- A "Connector" represents an endpoint by which requests are received
             and responses are returned.  Each Connector passes requests on to the
             associated "Container" (normally an Engine) for processing.

             By default, a non-SSL HTTP/1.1 Connector is established on port 8080.
             You can also enable an SSL HTTP/1.1 Connector on port 8443 by
             following the instructions below and uncommenting the second Connector
             entry.  SSL support requires the following steps (see the SSL Config
             HOWTO in the Tomcat 4.0 documentation bundle for more detailed
             * Download and install JSSE 1.0.2 or later, and put the JAR files
               into "$JAVA_HOME/jre/lib/ext".
             * Execute:
                 %JAVA_HOME%\bin\keytool -genkey -alias tomcat -keyalg RSA (Windows)
                 $JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA  (Unix)
               with a password value of "changeit" for both the certificate and
               the keystore itself.

             By default, DNS lookups are enabled when a web application calls
             request.getRemoteHost().  This can have an adverse impact on
             performance, so you can disable it by setting the
             "enableLookups" attribute to "false".  When DNS lookups are disabled,
             request.getRemoteHost() will return the String version of the
             IP address of the remote client.

        <!-- Define a non-SSL Coyote HTTP/1.1 Connector on port 8080 -->
        <!-- Marty Hall: changed port from 8080 to 80.
        <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
                   port="80" minProcessors="5" maxProcessors="75"
                   enableLookups="true" redirectPort="8443"
                   acceptCount="100" debug="0" connectionTimeout="20000"
                   useURIValidationHack="false" disableUploadTimeout="true" />
        <!-- Note : To disable connection timeouts, set connectionTimeout value
         to -1 -->

        <!-- Define a SSL Coyote HTTP/1.1 Connector on port 8443 -->
        <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
                   port="8443" minProcessors="5" maxProcessors="75"
               acceptCount="100" debug="0" scheme="https" secure="true"
                   useURIValidationHack="false" disableUploadTimeout="true">
          <Factory className="org.apache.coyote.tomcat4.CoyoteServerSocketFactory"
                   clientAuth="false" protocol="TLS" />

        <!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
        <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
                   port="8009" minProcessors="5" maxProcessors="75"
                   enableLookups="true" redirectPort="8443"
                   acceptCount="10" debug="0" connectionTimeout="0"

        <!-- Define an AJP 1.3 Connector on port 8009 -->
        <Connector className="org.apache.ajp.tomcat4.Ajp13Connector"
                   port="8009" minProcessors="5" maxProcessors="75"
                   acceptCount="10" debug="0"/>

        <!-- Define a Proxied HTTP/1.1 Connector on port 8082 -->
        <!-- See proxy documentation for more information about using this. -->
        <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
                   port="8082" minProcessors="5" maxProcessors="75"
                   acceptCount="100" debug="0" connectionTimeout="20000"
                   proxyPort="80" useURIValidationHack="false"
                   disableUploadTimeout="true" />

        <!-- Define a non-SSL legacy HTTP/1.1 Test Connector on port 8083 -->
        <Connector className="org.apache.catalina.connector.http.HttpConnector"
                   port="8083" minProcessors="5" maxProcessors="75"
                   enableLookups="true" redirectPort="8443"
                   acceptCount="10" debug="0" />

        <!-- Define a non-SSL HTTP/1.0 Test Connector on port 8084 -->
        <Connector className="org.apache.catalina.connector.http10.HttpConnector"
                   port="8084" minProcessors="5" maxProcessors="75"
                   enableLookups="true" redirectPort="8443"
                   acceptCount="10" debug="0" />

        <!-- An Engine represents the entry point (within Catalina) that processes
             every request.  The Engine implementation for Tomcat stand alone
             analyzes the HTTP headers included with the request, and passes them
             on to the appropriate Host (virtual host). -->

        <!-- You should set jvmRoute to support load-balancing via JK/JK2 ie :
        <Engine name="Standalone" defaultHost="localhost" debug="0" jvmRoute="jvm1">

        <!-- Define the top level container in our container hierarchy -->
        <Engine name="Standalone" defaultHost="localhost" debug="0">

          <!-- The request dumper valve dumps useful debugging information about
               the request headers and cookies that were received, and the response
               headers and cookies that were sent, for all requests received by
               this instance of Tomcat.  If you care only about requests to a
               particular virtual host, or a particular application, nest this
               element inside the corresponding <Host> or <Context> entry instead.

               For a similar mechanism that is portable to all Servlet 2.3
               containers, check out the "RequestDumperFilter" Filter in the
               example application (the source for this filter may be found in

               Request dumping is disabled by default.  Uncomment the following
               element to enable it. -->
          <Valve className="org.apache.catalina.valves.RequestDumperValve"/>

          <!-- Global logger unless overridden at lower levels -->
          <Logger className="org.apache.catalina.logger.FileLogger"
                  prefix="catalina_log." suffix=".txt"

          <!-- Because this Realm is here, an instance will be shared globally -->

          <!-- This Realm uses the UserDatabase configured in the global JNDI
               resources under the key "UserDatabase".  Any edits
               that are performed against this UserDatabase are immediately
               available for use by the Realm.  -->
          <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
                     debug="0" resourceName="UserDatabase"/>

          <!-- Comment out the old realm but leave here for now in case we
               need to go back quickly -->
          <Realm className="org.apache.catalina.realm.MemoryRealm" />

          <!-- Replace the above Realm with one of the following to get a Realm
               stored in a database and accessed via JDBC -->

          <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
             connectionName="test" connectionPassword="test"
                  userTable="users" userNameCol="user_name" userCredCol="user_pass"
              userRoleTable="user_roles" roleNameCol="role_name" />

          <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
             connectionName="scott" connectionPassword="tiger"
                  userTable="users" userNameCol="user_name" userCredCol="user_pass"
              userRoleTable="user_roles" roleNameCol="role_name" />

          <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
                  userTable="users" userNameCol="user_name" userCredCol="user_pass"
              userRoleTable="user_roles" roleNameCol="role_name" />

          <!-- Define the default virtual host -->
          <Host name="localhost" debug="0" appBase="webapps"
           unpackWARs="true" autoDeploy="true">

            <!-- Normally, users must authenticate themselves to each web app
                 individually.  Uncomment the following entry if you would like
                 a user to be authenticated the first time they encounter a
                 resource protected by a security constraint, and then have that
                 user identity maintained across *all* web applications contained
                 in this virtual host. -->
            <Valve className="org.apache.catalina.authenticator.SingleSignOn"

            <!-- Access log processes all requests for this virtual host.  By
                 default, log files are created in the "logs" directory relative to
                 $CATALINA_HOME.  If you wish, you can specify a different
                 directory with the "directory" attribute.  Specify either a relative
                 (to $CATALINA_HOME) or absolute path to the desired directory.
            <Valve className="org.apache.catalina.valves.AccessLogValve"
                     directory="logs"  prefix="localhost_access_log." suffix=".txt"
                     pattern="common" resolveHosts="false"/>

            <!-- Logger shared by all Contexts related to this virtual host.  By
                 default (when using FileLogger), log files are created in the "logs"
                 directory relative to $CATALINA_HOME.  If you wish, you can specify
                 a different directory with the "directory" attribute.  Specify either a
                 relative (to $CATALINA_HOME) or absolute path to the desired
            <Logger className="org.apache.catalina.logger.FileLogger"
                     directory="logs"  prefix="localhost_log." suffix=".txt"

            <!-- Define properties for each web application.  This is only needed
                 if you want to set non-default properties, or have web application
                 document roots in places other than the virtual host's appBase
                 directory.  -->

            <!-- Marty Hall: added to enable servlet reloading.
            <DefaultContext reloadable="true"/>
            <!-- Tomcat Root Context -->
            <!-- Marty Hall: uncommented the following to enable the ROOT context (default Web app).
            <Context path="" docBase="ROOT" debug="0"/>

            <!-- Tomcat Examples Context -->
            <Context path="/examples" docBase="examples" debug="0"
                     reloadable="true" crossContext="true">
              <Logger className="org.apache.catalina.logger.FileLogger"
                         prefix="localhost_examples_log." suffix=".txt"
              <Ejb   name="ejb/EmplRecord" type="Entity"

              <!-- If you wanted the examples app to be able to edit the
                   user database, you would uncomment the following entry.
                   Of course, you would want to enable security on the
                   application as well, so this is not done by default!
                   The database object could be accessed like this:

                   Context initCtx = new InitialContext();
                   Context envCtx = (Context) initCtx.lookup("java:comp/env");
                   UserDatabase database =
                        (UserDatabase) envCtx.lookup("userDatabase");
              <ResourceLink name="userDatabase" global="UserDatabase"

              <!-- PersistentManager: Uncomment the section below to test Persistent

                   saveOnRestart: If true, all active sessions will be saved
                     to the Store when Catalina is shutdown, regardless of
                     other settings. All Sessions found in the Store will be
                     loaded on startup. Sessions past their expiration are
                     ignored in both cases.
                   maxActiveSessions: If 0 or greater, having too many active
                     sessions will result in some being swapped out. minIdleSwap
                     limits this. -1 or 0 means unlimited sessions are allowed.
                     If it is not possible to swap sessions new sessions will
                     be rejected.
                     This avoids thrashing when the site is highly active.
                   minIdleSwap: Sessions must be idle for at least this long
                     (in seconds) before they will be swapped out due to
                     0 means sessions will almost always be swapped out after
                     use - this will be noticeably slow for your users.
                   maxIdleSwap: Sessions will be swapped out if idle for this
                     long (in seconds). If minIdleSwap is higher, then it will
                     override this. This isn't exact: it is checked periodically.
                     -1 means sessions won't be swapped out for this reason,
                     although they may be swapped out for maxActiveSessions.
                     If set to >= 0, guarantees that all sessions found in the
                     Store will be loaded on startup.
                   maxIdleBackup: Sessions will be backed up (saved to the Store,
                     but left in active memory) if idle for this long (in seconds),
                     and all sessions found in the Store will be loaded on startup.
                     If set to -1 sessions will not be backed up, 0 means they
                     should be backed up shortly after being used.

                   To clear sessions from the Store, set maxActiveSessions, maxIdleSwap,
                   and minIdleBackup all to -1, saveOnRestart to false, then restart
              <Manager className="org.apache.catalina.session.PersistentManager"
                    <Store className="org.apache.catalina.session.FileStore"/>
              <Environment name="maxExemptions" type="java.lang.Integer"
              <Parameter name="" value="context.param.value"
              <Resource name="jdbc/EmployeeAppDb" auth="SERVLET"
              <ResourceParams name="jdbc/EmployeeAppDb">
              <Resource name="mail/Session" auth="Container"
              <ResourceParams name="mail/Session">
              <ResourceLink name="linkToGlobalResource"




    i hope it may help you...

    Author Comment


    I already tried to use variations of the following config, but it does not fix the problem.

       <!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
        <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
                   port="8009" minProcessors="5" maxProcessors="75"
                   enableLookups="true" redirectPort="8443"
                   acceptCount="10" debug="0" connectionTimeout="0"

    Additional message I got was "BAD packet signature" error

    Nov 3, 2004 12:16:17 PM org.apache.jk.common.MsgAjp processHeader
    SEVERE: BAD packet signature 13
    00 0d 00 01 00                                   | .....
    Nov 3, 2004 12:16:17 PM org.apache.tomcat.util.threads.ThreadPool$ControlRunnable run
    SEVERE: Caught exception (java.lang.NullPointerException) executing org.apache.jk.common.SocketConnection@ddc581, terminating thread

    This sounds like the jk_nt_service.exe was sending the AJP connector a wrongly format message.  I wonder if it's something else in the configuration or it's an existing problem of jk_nt_service.exe

    Author Comment

    Follow-up on this subject: I was able to figure out part of the problem and devised a solution for it.

    1) There is a bug in jk_nt_exe that sends an invalid header.  I'd patched the code and the 'BAD packet signature' goes away.  

    2) However, the second problem of the NullPointerException still exists.
    There may be a bug in Tomcat connectors code.  I did not have time to look into this.

    3) To get around this problem and to get the service to shutdown properly, I used an undocumented feature that set the shudown_protocol to 'cmd' (instead of 'ajp13').  However, there are also bugs in implementation of this feature (perhaps this is why it's not documented as an option).  I fixed the problem and got the service to shutdown cleanly, similar to when using the '' script.  

    Since I found a fix and work-around and there have not been an solutions provided by the Exchange for almost two weeks now, I'd like to close this issue.

    Accepted Solution

    PAQed with points refunded (500)

    Community Support Moderator

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