title: Tomcat server became slow and unresponsive
body: <p>I have Spring Java 8 application deployed in Tomcat 8 server with 64
   GB and multi core processor.</p>
  
  <p>Application designed for number of user doing small operation every day and large process are scheduled to run in night time when there is no user operation. </p>
  
  <p>Sometimes application became slow and unresponsive, mainly in day time while user performing small operation. After server restart it became normal for few days.</p>
  
  <p>My observation while application slowness are</p>
  
  <ul>
  <li>There is no locked queries or session in DB side.</li>
  <li>There is no errors at that time.</li>
  <li>There is no <code>OutofMemory</code> or memory related exception at that time.</li>
  <li>I have checked the JVM through jVisual, in that heap memory keep growing and class count also increasing massively.</li>
  <li>I have tried clearing garbage manually, but no use.</li>
  </ul>
  
  <p>JVM argument:</p>
  
  <pre><code>-Xms8g-Xmx16g-XX:+AggressiveOpts-XX:+UseConcMarkSweepGC
  </code></pre>
  
  <p>I have the heap dump of JVM while it was slow, but i don't know how to find which <code>Class or Method or Thread</code> which causing the server slowness,</p>
  
  <p>Looking for suggestion to solve slowness.</p>