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| |
| <section id="Qpid-Java-FAQ"><title> |
| Qpid Java FAQ |
| </title> |
| |
| <section role="h2" id="QpidJavaFAQ-Purpose"> |
| <title>Purpose</title> |
| <para> |
| Here are a list of commonly asked questions and answers. Click on |
| the the bolded questions for the answer to unfold. If you have |
| any questions which are not on this list, please email our |
| qpid-user list. |
| </para> |
| |
| <section role="h3" id="QpidJavaFAQ-WhatisQpid-3F"><title> |
| What is Qpid ? |
| </title> |
| |
| <para> |
| The java implementation of Qpid is a pure Java message broker |
| that implements the AMQP protocol. Essentially, Qpid is a robust, |
| performant middleware component that can handle your messaging |
| traffic. |
| </para><para> |
| It currently supports the following features: |
| </para><itemizedlist> |
| <listitem><para>High performance header-based routing for messages |
| </para></listitem> |
| <listitem><para>All features required by the JMS 1.1 specification. Qpid |
| passes all tests in the Sun JMS compliance test suite |
| </para></listitem> |
| <listitem><para>Transaction support |
| </para></listitem> |
| <listitem><para>Persistence using the high performance Berkeley DB Java |
| Edition. The persistence layer is also pluggable should an |
| alternative implementation be required. The BDB store is |
| available from the <xref linkend="qpid_3rd-Party-Libraries"/> page |
| </para></listitem> |
| <listitem><para>Pluggable security using SASL. Any Java SASL provider can be |
| used |
| </para></listitem> |
| <listitem><para>Management using JMX and a custom management console built |
| using Eclipse RCP |
| </para></listitem> |
| <listitem><para>Naturally, interoperability with other clients including the |
| Qpid .NET, Python, Ruby and C++ implementations |
| </para></listitem> |
| </itemizedlist> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-WhyamIgettingaConfigurationExceptionatbrokerstartup-3F"><title> |
| Why am I getting a ConfigurationException at broker startup ? |
| </title> |
| |
| <section role="h4" id="QpidJavaFAQ-InvocationTargetException"><title> |
| InvocationTargetException |
| </title> |
| <para> |
| If you get a java.lang.reflect.InvocationTargetException on |
| startup, wrapped as ConfigurationException like this: |
| </para> |
| <programlisting> |
| Error configuring message broker: org.apache.commons.configuration.ConfigurationException: java.lang.reflect.InvocationTargetException |
| 2008-09-26 15:14:56,529 ERROR [main] server.Main (Main.java:206) - Error configuring message broker: org.apache.commons.configuration.ConfigurationException: java.lang.reflect.InvocationTargetException |
| org.apache.commons.configuration.ConfigurationException: java.lang.reflect.InvocationTargetException |
| at org.apache.qpid.server.security.auth.database.ConfigurationFilePrincipalDatabaseManager.initialisePrincipalDatabase(ConfigurationFilePrincipalDatabaseManager.java:158) |
| at org.apache.qpid.server.security.auth.database.ConfigurationFilePrincipalDatabaseManager.initialisePrincipalDatabases(ConfigurationFilePrincipalDatabaseManager.java:87) |
| at org.apache.qpid.server.security.auth.database.ConfigurationFilePrincipalDatabaseManager.<init>(ConfigurationFilePrincipalDatabaseManager.java:56) |
| at org.apache.qpid.server.registry.ConfigurationFileApplicationRegistry.initialise(ConfigurationFileApplicationRegistry.java:117) |
| at org.apache.qpid.server.registry.ApplicationRegistry.initialise(ApplicationRegistry.java:79) |
| at org.apache.qpid.server.registry.ApplicationRegistry.initialise(ApplicationRegistry.java:67) |
| at org.apache.qpid.server.Main.startup(Main.java:260) |
| at org.apache.qpid.server.Main.execute(Main.java:196) |
| at org.apache.qpid.server.Main.<init>(Main.java:96) |
| at org.apache.qpid.server.Main.main(Main.java:454) |
| at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) |
| at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) |
| at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) |
| at java.lang.reflect.Method.invoke(Method.java:597) |
| at com.intellij.rt.execution.application.AppMain.main(AppMain.java:90) |
| Caused by: java.lang.reflect.InvocationTargetException |
| at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) |
| at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) |
| at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) |
| at java.lang.reflect.Method.invoke(Method.java:597) |
| at org.apache.qpid.server.security.auth.database.ConfigurationFilePrincipalDatabaseManager.initialisePrincipalDatabase(ConfigurationFilePrincipalDatabaseManager.java:148) |
| </programlisting> |
| <para> |
| .. then it means you have a missing password file. |
| </para><para> |
| You need to create a password file for your deployment and update |
| your config.xml to reflect the location of the password file for |
| your instance. |
| </para><para> |
| The config.xml can be a little confusing in terms of element |
| names and file names for passwords. |
| </para><para> |
| To do this, you need to edit the passwordDir element for the |
| broker, which may have a comment to that effect: |
| </para> |
| <programlisting> |
| <passwordDir><!-- Change to the location --></passwordDir> |
| </programlisting> |
| <para> |
| The file should be named passwd by default but if you want to you |
| can change this by editing this element: |
| </para> |
| <programlisting> |
| <value>${passwordDir}/passwd</value> |
| </programlisting> |
| <!--h4--></section> |
| |
| |
| <section role="h4" id="QpidJavaFAQ-Cannotlocateconfigurationsourcenull-2Fvirtualhosts.xml"><title> |
| Cannot locate configuration source null/virtualhosts.xml |
| </title> |
| |
| <para> |
| If you get this message, wrapped inside a ConfigurationException |
| then you've come across a known issue, see JIRA <xref linkend="qpid_QPID-431"/> |
| </para><para> |
| The work around is to use a qualified path as the parameter value |
| for your -c option, rather than (as you migth be) starting the |
| broker from your installed etc directory. Even going up one level |
| and using a path relative to your £QPID_HOME directory |
| would sort this e.g qpid-server -c ./etc/myconfig.xml |
| </para> |
| <!--h4--></section> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIruntheQpidbroker-3F"><title> |
| How do I run |
| the Qpid broker ? |
| </title> |
| |
| <para> |
| The broker comes with a script for unix/linux/cygwin called |
| qpid-server, which can be found in the bin directory of the |
| installed package. This command can be executed without any |
| paramters and will then use the default configuration file |
| provided on install. |
| </para><para> |
| For the Windows OS, please use qpid-server.bat. |
| </para><para> |
| There's no need to set your classpath for QPID as the scripts |
| take care of that by adding jar's with classpath defining |
| manifest files to your classpath. |
| </para><para> |
| For more information on running the broker please see our |
| <xref linkend="Getting-Started"/> page. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIcreateaconnectionusingaURL-3F"><title> |
| How can I |
| create a connection using a URL ? |
| </title> |
| |
| <para> |
| Please see the <xref linkend="qpid_Connection-URL-Format"/> documentation. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIrepresentaJMSDestinationstringwithQPID-3F"><title> |
| How |
| do I represent a JMS Destination string with QPID ? |
| </title> |
| |
| <section role="h4" id="QpidJavaFAQ-Queues"><title> |
| Queues |
| </title> |
| |
| <para> |
| A queue can be created in QPID using the following URL format. |
| </para><para> |
| direct://amq.direct/<Destination>/<Queue |
| Name> |
| </para><para> |
| For example: |
| direct://amq.direct/<Destination>/simpleQueue |
| </para><para> |
| Queue names may consist of any mixture of digits, letters, and |
| underscores. |
| </para><para> |
| The <xref linkend="BindingURLFormat"/> is described in more |
| detail on it's own page. |
| </para> |
| <!--h4--></section> |
| |
| <section role="h4" id="QpidJavaFAQ-Topics"><title> |
| Topics |
| </title> |
| |
| <para> |
| A topic can be created in QPID using the following URL format. |
| </para><para> |
| topic://amq.topic/<Topic Subscription>/ |
| </para><para> |
| The topic subscription may only contain the letters A-Z and a-z |
| and digits 0-9. |
| </para><para> |
| The topic subscription is formed from a series of words that may |
| only contain the letters A-Z and a-z and digits 0-9. |
| The words are delimited by dots. Each dot represents a new level. |
| </para><para> |
| For example: stocks.nyse.ibm |
| </para><para> |
| Wildcards can be used on subscription with the following meaning. |
| </para><itemizedlist> |
| <listitem><para>match a single level |
| # match zero or more levels |
| </para></listitem> |
| </itemizedlist><para> |
| For example: |
| With two clients |
| 1 - stocks.*.ibm |
| 2 - stocks.#.ibm |
| </para><para> |
| Publishing stocks.nyse.ibm will be received by both |
| clients but stocks.ibm and stocks.world.us.ibm |
| will only be received by client 2. |
| </para><para> |
| The topic currently does not support wild cards. |
| </para> |
| <!--h4--></section> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIconnecttothebrokerusingJNDI-3F"><title> |
| How do I |
| connect to the broker using JNDI ? |
| </title> |
| |
| <para> |
| see <xref linkend="How-to-Use-JNDI"/> |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-I-27musingSpringandWeblogiccanyouhelpmewiththeconfigurationformovingovertoQpid-3F"><title> |
| I'm using Spring and Weblogic - can you help me with the |
| configuration for moving over to Qpid ? |
| </title> |
| |
| <para> |
| Here is a donated Spring configuration file <ulink |
| url="http://qpid.apache.org/qpid-java-faq.data/appContext.zip">appContext.zip</ulink> |
| which shows the config for Qpid side by side with |
| Weblogic. HtH ! |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIconfigurethelogginglevelforQpid-3F"><title> |
| How do |
| I configure the logging level for Qpid ? |
| </title> |
| |
| <para> |
| The system property |
| </para> |
| <programlisting> |
| amqj.logging.level |
| </programlisting> |
| <para> |
| can be used to configure the logging level. |
| For the broker, you can use the environment variable |
| AMQJ_LOGGING_LEVEL which is picked up by the qpid-run script |
| (called by qpid-server to start the broker) at runtime. |
| </para><para> |
| For client code that you've written, simply pass in a system |
| property to your command line to set it to the level you'd like |
| i.e. |
| </para> |
| <programlisting> |
| -Damqj.logging.level=INFO |
| </programlisting> |
| <para> |
| The log level for the broker defaults to INFO if the env variable |
| is not set, but you may find that your log4j properties affect |
| this. Setting the property noted above should address this. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIconfiguremyapplicationtouseQpidclientlogging-3F"><title> |
| How can I configure my application to use Qpid client |
| logging? |
| </title> |
| |
| <para> |
| If you don't already have a logging implementation in your |
| classpath you should add slf4-log4j12-1.4.0.jar and |
| log4j-1.2.12.jar. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIconfigurethebroker-3F"><title> |
| How can I |
| configure the broker ? |
| </title> |
| |
| <para> |
| The broker configuration is contained in the |
| <installed-dir>/etc/config.xml file. You can copy and edit |
| this file and then specify your own configuration file as a |
| parameter to the startup script using the -c flag i.e. |
| qpid-server -c <your_config_file's_path> |
| </para><para> |
| For more detailed information on configuration, please see |
| <xref linkend="qpid_Qpid-Design---Configuration"/> |
| </para><para> |
| |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-Whatportsdoesthebrokeruse"><title> |
| What ports |
| does the broker use? |
| </title> |
| |
| <para> |
| The broker defaults to use port 5672 at startup for AMQP |
| traffic. |
| If the management interface is enabled it starts on port 8999 by |
| default. |
| </para><para> |
| The JMX management interface actually requires 2 ports to |
| operate, the second of which is indicated to the client |
| application during connection initiation to the main (default: |
| 8999) port. Previously this second port has been chosen at random |
| during broker startup, however since Qpid 0.5 this has been fixed |
| to a port 100 higher than the main port(ie Default:9099) in order |
| to ease firewall navigation. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIchangetheportthebrokerusesatruntime-3F"><title> |
| How |
| can I change the port the broker uses at runtime ? |
| </title> |
| |
| <para> |
| The broker defaults to use port 5672 at startup for AMQP |
| traffic. |
| The broker also uses port 8999 for the JMX Management interface. |
| </para><para> |
| To change the AMQP traffic port use the -p flag at startup. To |
| change the management port use -m |
| i.e. qpid-server -p <port_number_to_use> -m |
| <port_number_to_use> |
| </para><para> |
| Use this to get round any issues on your host server with port |
| 5672/8999 being in use/unavailable. |
| </para><para> |
| For additional details on what ports the broker uses see <xref linkend="QpidJavaFAQ-Whatportsdoesthebrokeruse"/> FAQ |
| entry. |
| For more detailed information on configuration, please see |
| <xref linkend="qpid_Qpid-Design---Configuration"/> |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-WhatcommandlineoptionscanIpassintotheqpidserverscript-3F"><title> |
| What command line options can I pass into the qpid-server |
| script ? |
| </title> |
| |
| <para> |
| The following command line options are available: |
| </para> |
| |
| <para> |
| The following options are available: |
| </para><table> |
| <title> |
| Command Line Options |
| </title> |
| |
| <tgroup cols="3"> |
| <tbody> |
| <row> |
| <entry> |
| Option |
| </entry> |
| <entry> |
| Long Option |
| </entry> |
| <entry> |
| Description |
| </entry> |
| </row> |
| <row> |
| <entry> |
| b |
| </entry> |
| <entry> |
| bind |
| </entry> |
| <entry> |
| Bind to the specified address overriding any value in the |
| config file |
| </entry> |
| </row> |
| <row> |
| <entry> |
| c |
| </entry> |
| <entry> |
| config |
| </entry> |
| <entry> |
| Use the given configuration file |
| </entry> |
| </row> |
| <row> |
| <entry> |
| h |
| </entry> |
| <entry> |
| help |
| </entry> |
| <entry> |
| Prints list of options |
| </entry> |
| </row> |
| <row> |
| <entry> |
| l |
| </entry> |
| <entry> |
| logconfig |
| </entry> |
| <entry> |
| Use the specified log4j.xml file rather than that in the |
| etc directory |
| </entry> |
| </row> |
| <row> |
| <entry> |
| m |
| </entry> |
| <entry> |
| mport |
| </entry> |
| <entry> |
| Specify port to listen on for the JMX Management. Overrides |
| value in config file |
| </entry> |
| </row> |
| <row> |
| <entry> |
| p |
| </entry> |
| <entry> |
| port |
| </entry> |
| <entry> |
| Specify port to listen on. Overrides value in config file |
| </entry> |
| </row> |
| <row> |
| <entry> |
| v |
| </entry> |
| <entry> |
| version |
| </entry> |
| <entry> |
| Print version information and exit |
| </entry> |
| </row> |
| <row> |
| <entry> |
| w |
| </entry> |
| <entry> |
| logwatch |
| </entry> |
| <entry> |
| Specify interval for checking for logging config changes. |
| Zero means no checking |
| </entry> |
| </row> |
| </tbody> |
| </tgroup></table> |
| </section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIauthenticatewiththebroker-3FWhatuserid-26passwordshouldIuse-3F"><title> |
| How do I authenticate with the broker ? What user id & |
| password should I use ? |
| </title> |
| |
| <para> |
| You should login as user guest with password guest |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIcreatequeuesthatwillalwaysbeinstantiatedatbrokerstartup-3F"><title> |
| How do I create queues that will always be instantiated at |
| broker startup ? |
| </title> |
| |
| <para> |
| You can configure queues which will be created at broker startup |
| by tailoring a copy of the virtualhosts.xml file provided in the |
| installed qpid-version/etc directory. |
| </para><para> |
| So, if you're using a queue called 'devqueue' you can ensure that |
| it is created at startup by using an entry something like this: |
| </para> |
| <programlisting> |
| <virtualhosts> |
| <default>test</default> |
| <virtualhost> |
| <name>test</name> |
| <test> |
| <queue> |
| <name>devqueue</name> |
| <devqueue> |
| <exchange>amq.direct</exchange> |
| <maximumQueueDepth>4235264</maximumQueueDepth> <!-- 4Mb --> |
| <maximumMessageSize>2117632</maximumMessageSize> <!-- 2Mb --> |
| <maximumMessageAge>600000</maximumMessageAge> <!-- 10 mins --> |
| </devqueue> |
| </queue> |
| </test> |
| </virtualhost> |
| </virtualhosts> |
| </programlisting> |
| <para> |
| Note that the name (in thie example above the name is 'test') |
| element should match the virtualhost that you're using to create |
| connections to the broker. This is effectively a namespace used |
| to prevent queue name clashes etc. You can also see that we've |
| set the 'test' virtual host to be the default for any connections |
| which do not specify a virtual host (in the <default> tag). |
| </para><para> |
| You can amend the config.xml to point at a different |
| virtualhosts.xml file by editing the <virtualhosts/> |
| element. |
| </para><para> |
| So, for example, you could tell the broker to use a file in your |
| home directory by creating a new config.xml file with the |
| following entry: |
| </para><para> |
| <virtualhosts>/home/myhomedir/virtualhosts.xml</virtualhosts> |
| </para><para> |
| You can then pass this amended config.xml into the broker at |
| startup using the -c flag i.e. |
| qpid-server -c <path>/config.xml |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIcreatequeuesatruntime-3F"><title> |
| How do I |
| create queues at runtime? |
| </title> |
| |
| <para> |
| Queues can be dynamically created at runtime by creating a |
| consumer for them. After they have been created and bound (which |
| happens automatically when a JMS Consumer is created) a publisher |
| can send messages to them. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoItunethebroker-3F"><title> |
| How do I tune |
| the broker? |
| </title> |
| |
| <para> |
| There are a number of tuning options available, please see the |
| <xref linkend="How-to-Tune-M3-Java-Broker-Performance"/> page for more information. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-Wheredoundeliverablemessagesendup-3F"><title> |
| Where do |
| undeliverable messages end up ? |
| </title> |
| |
| <para> |
| At present, messages with an invalid routing key will be returned |
| to the sender. If you register an exception listener for your |
| publisher (easiest to do by making your publisher implement the |
| ExceptionListener interface and coding the onException method) |
| you'll see that you end up in onException in this case. You can |
| expect to be catching a subclass of |
| org.apache.qpid.AMQUndeliveredException. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-CanIconfigurethenameoftheQpidbrokerlogfileatruntime-3F"><title> |
| Can I configure the name of the Qpid broker log file at |
| runtime ? |
| </title> |
| |
| <para> |
| If you simply start the Qpid broker using the default |
| configuration, then the log file is written to |
| $QPID_WORK/log/qpid.log |
| </para><para> |
| This is not ideal if you want to run several instances from one |
| install, or acrhive logs to a shared drive from several hosts. |
| </para><para> |
| To make life easier, there are two optional ways to configure the |
| naming convention used for the broker log. |
| </para> |
| |
| <section role="h4" id="QpidJavaFAQ-Settingaprefixorsuffix"><title> |
| Setting a prefix |
| or suffix |
| </title> |
| |
| <para> |
| Users should set the following environment variables before |
| running qpid-server: |
| </para><para> |
| QPID_LOG_PREFIX - will prefix the log file name with the |
| specified value e.g. if you set this value to be the name of your |
| host (for example) it could look something like host123qpid.log |
| </para><para> |
| QPID_LOG_SUFFIX - will suffix the file name with the specified |
| value e.g. if you set this value to be the name of your |
| application (for example) if could look something like |
| qpidMyApp.log |
| </para> |
| <!--h4--></section> |
| |
| <section role="h4" id="QpidJavaFAQ-IncludingthePID"><title> |
| Including the PID |
| </title> |
| |
| <para> |
| Setting either of these variables to the special value PID will |
| introduce the process id of the java process into the file name |
| as a prefix or suffix as specified** |
| </para> |
| <!--h4--></section> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-Myclientapplicationappearstohavehung-3F"><title> |
| My |
| client application appears to have hung? |
| </title> |
| |
| <para> |
| The client code currently has various timeouts scattered |
| throughout the code. These can cause your client to appear like |
| it has hung when it is actually waiting for the timeout ot |
| compelete. One example is when the broker becomes non-responsive, |
| the client code has a hard coded 2 minute timeout that it will |
| wait when closing a connection. These timeouts need to be |
| consolidated and exposed. see <xref linkend="qpid_QPID-429"/> |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIcontacttheQpidteam-3F"><title> |
| How do I |
| contact the Qpid team ? |
| </title> |
| |
| <para> |
| For general questions, please subscribe to the |
| <ulink url="mailto:users@qpid.apache.org">users@qpid.apache.org</ulink> mailing list. |
| </para><para> |
| For development questions, please subscribe to the |
| <ulink url="mailto:dev@qpid.apache.org">dev@qpid.apache.org</ulink> mailing list. |
| </para><para> |
| More details on these lists are available on our <xref linkend="qpid_Mailing-Lists"/> |
| page. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIchangeauser-27spasswordwhilethebrokerisup-3F"><title> |
| How can I change a user's password while the broker is up ? |
| </title> |
| |
| <para> |
| You can do this via the <xref linkend="qpid_Qpid-JMX-Management-Console"/>. To |
| do this simply log in to the management console as an admin user |
| (you need to have created an admin account in the |
| jmxremote.access file first) and then select the 'UserManagement' |
| mbean. Select the user in the table and click the Set Password |
| button. Alternatively, update the password file and use the |
| management console to reload the file with the button at the |
| bottom of the 'UserManagement' view. In both cases, this will |
| take effect when the user next logs in i.e. will not cause them |
| to be disconnected if they are already connected. |
| </para><para> |
| For more information on the Management Console please see our |
| <xref linkend="Qpid-JMX-Management-Console-User-Guide"/> |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowdoIknowifthereisaconsumerforamessageIamgoingtosend-3F"><title> |
| How do I know if there is a consumer for a message I am going |
| to send? |
| </title> |
| |
| <para> |
| Knowing that there is a consumer for a message is quite tricky. |
| That said using the qpid.jms.Session#createProducer with |
| immediate and mandatory set to true will get you part of the way |
| there. |
| </para><para> |
| If you are publishing to a well known queue then immediate will |
| let you know if there is any consumer able to pre-fetch that |
| message at the time you send it. If not it will be returned to |
| you on your connection listener. |
| </para><para> |
| If you are sending to a queue that the consumer creates then the |
| mandatory flag will let you know if they have not yet created |
| that queue. |
| </para><para> |
| These flags will not be able to tell you if the consuming |
| application has received the message and is able to process it. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-HowcanIinspectthecontentsofmyMessageStore-3F"><title> |
| How |
| can I inspect the contents of my MessageStore? |
| </title> |
| |
| <para> |
| The management console can be used to interogate an active |
| broker and browse the contents of a queue.See the <xref linkend="qpid_Qpid-JMX-Management-Console"/> |
| page for further details. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-Whyaremytransientmessagesbeingsoslow-3F"><title> |
| Why are |
| my transient messages being so slow? |
| </title> |
| |
| <para> |
| You should check that you aren't sending persistent messages, |
| this is the default. If you want to send transient messages you |
| must explicitly set this option when instantiating your |
| MessageProducer or on the send() method. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-Whydoesmyproducerfillupthebrokerwithmessages-3F"><title> |
| Why |
| does my producer fill up the broker with messages? |
| </title> |
| |
| <para> |
| Switch on producer flow control to prevent temporary spikes in |
| message production over-filling the broker. |
| |
| Of course, if the long-term rate of message production exceeds |
| the rate of message |
| consumption then that is an architectural problem that can only |
| be temporarily mitigated by producer flow control. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-ThebrokerkeepsthrowinganOutOfMemoryexception-3F"><title> |
| The |
| broker keeps throwing an OutOfMemory exception? |
| </title> |
| |
| <para> |
| The broker can no longer store any more messages in memory. This |
| is particular evident if you are using the MemoryMessageStore. To |
| alleviate this issue you should ensure that your clients are |
| consuming all the messages from the broker. |
| </para><para> |
| You may also want to increase the memory allowance to the broker |
| though this will only delay the exception if you are publishing |
| messages faster than you are consuming. See <xref linkend="qpid_Java-Environment-Variables"/> for |
| details of changing the memory settings. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-WhyamIgettingabrokersideexceptionwhenItrytopublishtoaqueueoratopic-3F"><title> |
| Why am I getting a broker side exception when I try to |
| publish to a queue or a topic ? |
| </title> |
| |
| <para> |
| If you get a stack trace like this when you try to publish, then |
| you may have typo'd the exchange type in your queue or topic |
| declaration. Open your virtualhosts.xml and check that the |
| </para> |
| <programlisting> |
| <exchange>amq.direct</exchange> |
| </programlisting> |
| |
| <programlisting> |
| 2009-01-12 15:26:27,957 ERROR [pool-11-thread-2] protocol.AMQMinaProtocolSession (AMQMinaProtocolSession.java:365) - Unexpected exception while processing frame. Closing connection. |
| java.lang.NullPointerException |
| at org.apache.qpid.server.security.access.PrincipalPermissions.authorise(PrincipalPermissions.java:398) |
| at org.apache.qpid.server.security.access.plugins.SimpleXML.authorise(SimpleXML.java:302) |
| at org.apache.qpid.server.handler.QueueBindHandler.methodReceived(QueueBindHandler.java:111) |
| at org.apache.qpid.server.handler.ServerMethodDispatcherImpl.dispatchQueueBind(ServerMethodDispatcherImpl.java:498) |
| at org.apache.qpid.framing.amqp_8_0.QueueBindBodyImpl.execute(QueueBindBodyImpl.java:167) |
| at org.apache.qpid.server.state.AMQStateManager.methodReceived(AMQStateManager.java:204) |
| at org.apache.qpid.server.protocol.AMQMinaProtocolSession.methodFrameReceived(AMQMinaProtocolSession.java:295) |
| at org.apache.qpid.framing.AMQMethodBodyImpl.handle(AMQMethodBodyImpl.java:93) |
| at org.apache.qpid.server.protocol.AMQMinaProtocolSession.frameReceived(AMQMinaProtocolSession.java:235) |
| at org.apache.qpid.server.protocol.AMQMinaProtocolSession.dataBlockReceived(AMQMinaProtocolSession.java:191) |
| at org.apache.qpid.server.protocol.AMQPFastProtocolHandler.messageReceived(AMQPFastProtocolHandler.java:244) |
| at org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.messageReceived(AbstractIoFilterChain.java:703) |
| at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:362) |
| at org.apache.mina.common.support.AbstractIoFilterChain.access$1200(AbstractIoFilterChain.java:54) |
| at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:800) |
| at org.apache.qpid.pool.PoolingFilter.messageReceived(PoolingFilter.java:371) |
| at org.apache.mina.filter.ReferenceCountingIoFilter.messageReceived(ReferenceCountingIoFilter.java:96) |
| at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:362) |
| at org.apache.mina.common.support.AbstractIoFilterChain.access$1200(AbstractIoFilterChain.java:54) |
| at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:800) |
| at org.apache.mina.filter.codec.support.SimpleProtocolDecoderOutput.flush(SimpleProtocolDecoderOutput.java:60) |
| at org.apache.mina.filter.codec.QpidProtocolCodecFilter.messageReceived(QpidProtocolCodecFilter.java:174) |
| at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:362) |
| at org.apache.mina.common.support.AbstractIoFilterChain.access$1200(AbstractIoFilterChain.java:54) |
| at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:800) |
| at org.apache.qpid.pool.Event$ReceivedEvent.process(Event.java:86) |
| at org.apache.qpid.pool.Job.processAll(Job.java:110) |
| at org.apache.qpid.pool.Job.run(Job.java:149) |
| at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885) |
| at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907) |
| at java.lang.Thread.run(Thread.java:619) |
| </programlisting> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-WhyistherealotofAnonymousIoServicethreads"><title> |
| Why |
| is there a lot of AnonymousIoService threads |
| </title> |
| |
| <para> |
| These threads are part of the thread pool used by Mina to process |
| the socket. In the future we may provide tuning guidelines but at |
| this point we have seen no performance implications from the |
| current configuration. As the threads are part of a pool they |
| should remain inactive until required. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ--22unabletocertifytheprovidedSSLcertificateusingthecurrentSSLtruststore-22whenconnectingtheManagementConsoletothebroker."><title> |
| "unable to certify the provided SSL certificate using the |
| current SSL trust store" when connecting the Management Console |
| to the broker. |
| </title> |
| |
| <para> |
| You have not configured the console's SSL trust store properly, |
| see <xref linkend="qpid_Management-Console-Security"/> for |
| more details. |
| </para> |
| <!--h3--></section> |
| |
| <section role="h3" id="QpidJavaFAQ-CanauseTCPKEEPALIVEorAMQPheartbeatingtokeepmyconnectionopen-3F"><title> |
| Can a use TCP_KEEPALIVE or AMQP heartbeating to keep my |
| connection open? |
| </title> |
| |
| <para> |
| See <xref linkend="qpid_Configure-Broker-and-Client-Heartbeating"/> |
| </para> |
| |
| <!--h3--></section> |
| <!--h2--></section> |
| |
| |
| |
| </section> |
