title: tomcat 8 common.loader server.loader shared.loader
body: <p>I'm using tomcat 8, in </p>
  
  <blockquote>
    <p>tomcat-home/config/catalina.properties</p>
  </blockquote>
  
  <p>, there are sections about </p>
  
  <blockquote>
    <p>common.loader, server.loader and shared.loader</p>
  </blockquote>
  
  <p>However, on tomcat document about class loader(<a href="https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html" rel="noreferrer">https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html</a>), there is only has description about <code>common.loader</code>.</p>
  
  <p>So what are differences between these 3 loader? (I know <code>common class loader contains additional classes that are made visible to both Tomcat internal classes and to all web applications. Normally, application classes should NOT be placed here. If left blank, server.loader and shared.loader will use common.loader config. Webapp common jar can be placed in shared.loader.</code> But what are other differences? such as differences between common.loader and server.loader, server.loader and shared.loader etc?)</p>