| <html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Apache Tomcat Configuration Reference (6.0.39) - The Loader Component</title><meta name="author" content="Craig R. McClanahan"><style type="text/css" media="print"> | |
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| The Apache Tomcat Servlet/JSP Container | |
| " border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 6.0</font></h1><font face="arial,helvetica,sanserif">Version 6.0.39, Jan 27 2014</font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../images/asf-logo.gif" align="right" alt="Apache Logo" border="0"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap="nowrap" class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Config Ref. Home</a></li></ul><p><strong>Top Level Elements</strong></p><ul><li><a href="server.html">Server</a></li><li><a href="service.html">Service</a></li></ul><p><strong>Executors</strong></p><ul><li><a href="executor.html">Executor</a></li></ul><p><strong>Connectors</strong></p><ul><li><a href="http.html">HTTP</a></li><li><a href="ajp.html">AJP</a></li></ul><p><strong>Containers</strong></p><ul><li><a href="context.html">Context</a></li><li><a href="engine.html">Engine</a></li><li><a href="host.html">Host</a></li><li><a href="cluster.html">Cluster</a></li></ul><p><strong>Nested Components</strong></p><ul><li><a href="globalresources.html">Global Resources</a></li><li><a href="listeners.html">Listeners</a></li><li><a href="loader.html">Loader</a></li><li><a href="manager.html">Manager</a></li><li><a href="realm.html">Realm</a></li><li><a href="resources.html">Resources</a></li><li><a href="valve.html">Valve</a></li></ul><p><strong>Cluster Elements</strong></p><ul><li><a href="cluster.html">Cluster</a></li><li><a href="cluster-manager.html">Manager</a></li><li><a href="cluster-channel.html">Channel</a></li><li><a href="cluster-membership.html">Channel/Membership</a></li><li><a href="cluster-sender.html">Channel/Sender</a></li><li><a href="cluster-receiver.html">Channel/Receiver</a></li><li><a href="cluster-interceptor.html">Channel/Interceptor</a></li><li><a href="cluster-valve.html">Valve</a></li><li><a href="cluster-deployer.html">Deployer</a></li><li><a href="cluster-listener.html">ClusterListener</a></li></ul><p><strong>Other</strong></p><ul><li><a href="filter.html">Filter</a></li><li><a href="systemprops.html">System properties</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Apache Tomcat Configuration Reference</h1><h2>The Loader Component</h2><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><!--()--></a><a name="Table_of_Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote> | |
| <ul><li><a href="#Introduction">Introduction</a></li><li><a href="#Attributes">Attributes</a><ol><li><a href="#Common_Attributes">Common Attributes</a></li><li><a href="#Standard_Implementation">Standard Implementation</a></li></ol></li><li><a href="#Nested_Components">Nested Components</a></li><li><a href="#Special_Features">Special Features</a><ol><li><a href="#Logging">Logging</a></li></ol></li></ul> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>The <strong>Loader</strong> element represents the <em>web | |
| application class loader</em> that will be used to load Java | |
| classes and resources for your web application. Such | |
| a class loader must follow the requirements of the Servlet | |
| Specification, and load classes from the following locations:</p> | |
| <ul> | |
| <li>From the <code>/WEB-INF/classes</code> directory inside your | |
| web application.</li> | |
| <li>From JAR files in the <code>/WEB-INF/lib</code> directory | |
| inside your web application.</li> | |
| <li>From resources made available by Catalina to all web | |
| applications globally.</li> | |
| </ul> | |
| <p>A Loader element MAY be nested inside a <a href="context.html">Context</a> | |
| component. If it is not included, a default Loader configuration will be | |
| created automatically, which is sufficient for most requirements.</p> | |
| <p>For a more in-depth description of the class loader hierarchy | |
| that is implemented by Catalina, see <a href="../class-loader-howto.html">the ClassLoader HowTo</a>.</p> | |
| <blockquote><em> | |
| <p>The description below uses the variable name $CATALINA_BASE to refer the | |
| base directory against which most relative paths are resolved. If you have | |
| not configured Tomcat 6 for multiple instances by setting a CATALINA_BASE | |
| directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME, | |
| the directory into which you have installed Tomcat 6.</p> | |
| </em></blockquote> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Attributes"><strong>Attributes</strong></a></font></td></tr><tr><td><blockquote> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Common Attributes"><!--()--></a><a name="Common_Attributes"><strong>Common Attributes</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>All implementations of <strong>Loader</strong> | |
| support the following attributes:</p> | |
| <table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Attribute</font></th><th width="85%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>className</code></td><td align="left" valign="center"> | |
| <p>Java class name of the implementation to use. This class must | |
| implement the <code>org.apache.catalina.Loader</code> interface. | |
| If not specified, the standard value (defined below) will be used.</p> | |
| </td></tr><tr><td align="left" valign="center"><code>delegate</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> if you want the class loader to follow | |
| the standard Java2 delegation model, and attempt to load classes from | |
| parent class loaders <strong>before</strong> looking inside the web | |
| application. Set to <code>false</code> (the default) to have the | |
| class loader look inside the web application first, before asking | |
| parent class loaders to find requested classes or resources.</p> | |
| </td></tr><tr><td align="left" valign="center"><code>reloadable</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> if you want Catalina to monitor classes in | |
| <code>/WEB-INF/classes/</code> and <code>/WEB-INF/lib</code> for | |
| changes, and automatically reload the web application if a change | |
| is detected. This feature is very useful during application | |
| development, but it requires significant runtime overhead and is | |
| not recommended for use on deployed production applications. You | |
| can use the <a href="../manager-howto.html">Manager</a> web | |
| application, however, to trigger reloads of deployed applications | |
| on demand.</p> | |
| <p><strong>NOTE</strong> - The value for this property will be | |
| inherited from the <code>reloadable</code> attribute you set on | |
| the surrounding <a href="context.html">Context</a> component, | |
| and any value you explicitly set here will be replaced.</p> | |
| </td></tr></table> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Standard Implementation"><!--()--></a><a name="Standard_Implementation"><strong>Standard Implementation</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>The standard implementation of <strong>Loader</strong> is | |
| <strong>org.apache.catalina.loader.WebappLoader</strong>. | |
| It supports the following additional attributes (in addition to the | |
| common attributes listed above):</p> | |
| <table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Attribute</font></th><th width="85%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>loaderClass</code></td><td align="left" valign="center"> | |
| <p>Java class name of the <code>java.lang.ClassLoader</code> | |
| implementation class to use. If not specified, the default value is | |
| <code>org.apache.catalina.loader.WebappClassLoader</code>. Custom | |
| <strong>loaderClass</strong> implementations must extend | |
| <code>org.apache.catalina.loader.WebappClassLoader</code>.</p> | |
| </td></tr><tr><td align="left" valign="center"><code>searchExternalFirst</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> if you want repositories outside | |
| of <code>WEB-INF/classes</code> and <code>WEB-INF/lib</code> to | |
| be searched first. Default value is <code>false</code>.</p> | |
| </td></tr></table> | |
| </blockquote></td></tr></table> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Nested Components"><!--()--></a><a name="Nested_Components"><strong>Nested Components</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>No components may be nested inside a <strong>Loader</strong> element.</p> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Special Features"><!--()--></a><a name="Special_Features"><strong>Special Features</strong></a></font></td></tr><tr><td><blockquote> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Logging"><strong>Logging</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>A loader is associated with the log category based on its classname.</p> | |
| </blockquote></td></tr></table> | |
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