title: Java server cpu usage at 100% after two days continous running with about 110 users
body: <p>I have a tomcat  6.0.20, apr 1.2, jdk 1.6.0_15 with mysql 5.1.38 running on a rhel box with 4 GB ram. There is one simple jsp/servlet application on it with 5 users, one struts 1.2.0.9 with 64 users on it and one struts 2.0 application with 35 users on it. The struts 2.0 users make an entry every second, about 900 entries in a day. I am also using toplink for persistence in the last two applications. I have declared all non referenced objects to null, in the code, have applied production values for config files from the struts 2 site and from the tomcat site. Applied thread caching in mysql, reduce wait_timeout and interactive_timeout to be equivalent to session timeout of tomcat.Increased file descriptors in linux. Reworked queries. Examined the thread dump, watched gc stats, applied above changes on basis of this, </p>
  
  <blockquote>
    <p>YET still facing "java.lang.OutOfMemoryError" error.</p>
  </blockquote>
  
  <p>at different times its for different things, sometimes its Servlet.service(), sometimes its image.servlet, sometimes it jasper that causes it. </p>
  
  <blockquote>
    <p>extremely frustrtating, as the errors are not constant but keep changing over time</p>
    
    <p>Any help please would be greatly
    appreciated!!!</p>
  </blockquote>
  
  <p>JAVA_OPTS=-server -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -XX:+CMSParallelRemarkEnabled 
  (tomcat manager reports 34 mb empty so have not used permsize, mx and mn etc.)</p>
  
  <p>persistence.xml </p>
  
  <pre><code> &lt;property name="toplink.jdbc.url" value="jdbc:mysql://localhost:3306/dbname?autoReconnect=false"/&gt;
  </code></pre>
  
  <p>
  
  
  
  </p>
  
  <p>server.xml</p>
  
  <pre><code>&lt;Connector port="80" protocol="HTTP/1.1" connectionTimeout="2000" redirectPort="8443" compression="on" compressableMimeType="application/octet-stream,text/html,text/xml,text/plain,application/x-javascript,image/gif,text/css,image/gif,application/vnd.ms-excel,application/pdf" enableLookups="false"/&gt;
  </code></pre>
  
  <p>context.xml</p>
  
  <pre><code>&lt;Context reloadable="false" delegate="false" privileged="false"&gt;
  </code></pre>