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   <title>Troubleshooting Locked Files on Windows</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="troubleshooting.html" title="Chapter&nbsp;33.&nbsp;Troubleshooting"><link rel="prev" href="troubleshooting.html" title="Chapter&nbsp;33.&nbsp;Troubleshooting"><link rel="next" href="preventing-memory-leaks.html" title="Preventing Memory Leaks"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script>
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            Version: 9.4.27-SNAPSHOT</span></td><td style="width: 50%"></td></tr></table><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Troubleshooting Locked Files on Windows</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="troubleshooting.html"><i class="fa fa-chevron-left" aria-hidden="true"></i> Previous</a>&nbsp;</td><th width="60%" align="center">Chapter&nbsp;33.&nbsp;Troubleshooting<br><a accesskey="p" href="index.html"><i class="fa fa-home" aria-hidden="true"></i> Home</a></th><td width="20%" align="right">&nbsp;<a accesskey="n" href="preventing-memory-leaks.html">Next <i class="fa fa-chevron-right" aria-hidden="true"></i></a></td></tr></table><hr></div><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="jetty-callout"><h5 class="callout"><a href="http://www.webtide.com/">Contact the core Jetty developers at
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      </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="troubleshooting-locked-files-on-windows"></a>Troubleshooting Locked Files on Windows</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="troubleshooting-locked-files-on-windows.html#_remedy">Remedy</a></span></dt><dt><span class="section"><a href="troubleshooting-locked-files-on-windows.html#_alternate_remedy">Alternate Remedy</a></span></dt></dl></div><p>Jetty buffers static content for webapps such as HTML files, CSS files, images, etc.
If you are using NIO connectors, Jetty uses memory-mapped files to do this.
The problem is that on Windows, memory mapping a file causes the file to lock, so that you cannot update or replace the file.
Effectively this means that you have to stop Jetty to update a file.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_remedy"></a>Remedy</h3></div></div></div><p>Jetty provides a configuration switch for the <code class="literal">DefaultServlet</code> that enables or disables the use of memory-mapped files.
If you are running on Windows and are having file-locking problems, you should set this switch to disable memory-mapped file buffers.
Use one of the following options to configure the switch.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="_using_override_web_xml"></a>Using override-web.xml</h4></div></div></div><p>An <a class="link" href="override-web-xml.html" title="Jetty override-web.xml">override-web.xml</a> file can be placed in your webapp&#8217;s <code class="literal">WEB-INF</code> directory to change the default setting of the <code class="literal">DefaultServlet</code> for memory-mapped file buffers.
Create an <code class="literal">override-web.xml</code> file with appropriate headers for your version of the servlet specification, and place the following inside the <code class="literal">&lt;web-app&gt;</code> element:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code> &lt;servlet&gt;
   &lt;servlet-name&gt;default&lt;/servlet-name&gt;
   &lt;init-param&gt;
     &lt;param-name&gt;useFileMappedBuffer&lt;/param-name&gt;
     &lt;param-value&gt;false&lt;/param-value&gt;
   &lt;/init-param&gt;
 &lt;/servlet&gt;</code></pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="_using_a_context_xml_file"></a>Using a Context XML File</h4></div></div></div><p>You can create or update a context xml file that configures your webapp to apply the setting to disable memory-mapped file buffers.
Add the following to your context xml file:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>  &lt;Call name="setInitParameter"&gt;
      &lt;Arg&gt;org.eclipse.jetty.servlet.Default.useFileMappedBuffer&lt;/Arg&gt;
      &lt;Arg&gt;false&lt;/Arg&gt;
  &lt;/Call&gt;</code></pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="_using_the_jetty_maven_plugin"></a>Using the Jetty Maven Plugin</h4></div></div></div><p>If you don&#8217;t want to use either of the other two solutions, you can configure the plugin directly to disable memory-mapped file buffers.
Add the following to the plugin&#8217;s configuration under the <code class="literal">&lt;webApp&gt;</code> element:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>  &lt;_initParams&gt;
          &lt;org.eclipse.jetty.servlet.Default.useFileMappedBuffer&gt;false&lt;/org.eclipse.jetty.servlet.Default.useFileMappedBuffer&gt;
  &lt;/_initParams&gt;</code></pre></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_alternate_remedy"></a>Alternate Remedy</h3></div></div></div><p>You can force a <code class="literal">WebAppContext</code> to always copy a web app directory on deployment.
The base directory of your web app (i.e. the root directory where your static content exists) will be copied to the <a class="link" href="ref-temporary-directories.html" title="Temporary Directories">temp directory</a>.
Configure this in an xml file like so:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>&lt;New id="myWebAppContext"  class="org.eclipse.jetty.webapp.WebAppContext"&gt;
  &lt;Set name="contextPath"&gt;/&lt;/Set&gt;
  &lt;Set name="war"&gt;./webapps/fredapp&lt;/Set&gt;
  &lt;Set name="copyWebDir"&gt;true&lt;/Set&gt;
  .
  .
&lt;/New&gt;</code></pre><div class="blockquote"><blockquote class="blockquote"><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title"><i class="fa fa-asterisk" aria-hidden="true"></i> Note</h3><p>Be careful with this option when using an explicitly settemp directory name - as the name of the temp directory will not unique across redeployments, copying the static content into the same directory name each time may not avoid the locking problem.</p></div></blockquote></div></div></div><script type="text/javascript">
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