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   <title>Chapter&nbsp;33.&nbsp;Troubleshooting</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="jetty-ref-guide.html" title="Part&nbsp;V.&nbsp;Jetty Reference Guide"><link rel="prev" href="override-web-xml.html" title="Jetty override-web.xml"><link rel="next" href="troubleshooting-locked-files-on-windows.html" title="Troubleshooting Locked Files on Windows"><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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      </p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a name="troubleshooting"></a>Chapter&nbsp;33.&nbsp;Troubleshooting</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="troubleshooting.html#troubleshooting-zip-exceptions">Troubleshooting Zip Exceptions</a></span></dt><dt><span class="section"><a href="troubleshooting-locked-files-on-windows.html">Troubleshooting Locked Files on Windows</a></span></dt><dt><span class="section"><a href="preventing-memory-leaks.html">Preventing Memory Leaks</a></span></dt><dt><span class="section"><a href="troubleshooting-slow-deployment.html">Troubleshooting Slow Deployment</a></span></dt><dt><span class="section"><a href="security-reports.html">Jetty Security Reports</a></span></dt></dl></div><p>This is a collection of helpful tricks and tips that we have come across to address odd issues that might arise.</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="troubleshooting-zip-exceptions"></a>Troubleshooting Zip Exceptions</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="troubleshooting.html#remedy">Remedy</a></span></dt></dl></div><p>A Zip exception occurs when Jetty rereads a Jar or WAR file.</p><p>The JVM maintains a cache of zip file indexes, and does not support hot replacement of zip files.
Thus if you redeploy a web application using the same WAR or Jar files, exceptions occur when Jetty rereads the jars.
See <a class="link" href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4774421" target="_top">Oracle Bug 4774421</a> for more information.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="remedy"></a>Remedy</h3></div></div></div><p>The remedy is to avoid hot replacing Jar or WAR files, which can be difficult if you are using the
<a class="link" href="configuring-specific-webapp-deployment.html" title="Configuring a Specific Web Application Deployment">Webapp Provider</a>.
You can use the following techniques to reduce exposure to this issue:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">Deploy unpacked classes in the <code class="literal">WEB-INF/classes</code> directory rather than as a Jar file under <code class="literal">WEB-INF/lib</code>.</li><li class="listitem">Deploy all WAR and Jar files with a version number in their filename or path.
If the code changes, a new version number applies, avoiding the cache problem.</li><li class="listitem">Deploy a packed WAR file with the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.27.v20190418/org/eclipse/jetty/webapp/WebAppContext.html#setExtractWAR(boolean)" target="_top">setExtractWAR</a> option set to true.
This causes the WAR to be extracted to a <a class="link" href="ref-temporary-directories.html" title="Temporary Directories">temporary directory</a> and thus to a new location.
This might not be sufficient if you want to hot-replace and re-extract the WAR, so you might also need to use <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.27.v20190418/org/eclipse/jetty/webapp/WebAppContext.html#setCopyWebInf(boolean)" target="_top">WebAppContext.setCopyWebInf(true)</a>, which (re)copies just the WEB-INF directory to a different location.</li><li class="listitem">Deploy an unpacked WAR file with the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.27.v20190418/org/eclipse/jetty/webapp/WebAppContext.html#setCopyWebDir(boolean)" target="_top">setCopyWebDir</a> option set to true.
This causes the directory to be extracted to a new location.</li></ul></div><p>If you have problems with <a class="link" href="troubleshooting-locked-files-on-windows.html" title="Troubleshooting Locked Files on Windows">Windows file-locking</a> preventing static file editing (such as JSP or HTML), use the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.27.v20190418/org/eclipse/jetty/webapp/WebAppContext.html#setCopyWebDir(boolean)" target="_top">WebAppContext .setCopyWebDir(true)</a> option.</p></div></div></div><script type="text/javascript">
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