title: Java using more memory than the allocated memory
body: <p>An Apache Tomcat (Atlassian Confluence) instance is started using the following Java options:</p>
  
  <pre><code>JAVA_OPTS="-Xms256m -Xmx512m -XX:MaxPermSize=256m -Djava.awt.headless=true "
  </code></pre>
  
  <p>However I see that after starting up it quickly eats through most of the 1GB of memory that is available on my virtual server.</p>
  
  <pre><code> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
   6082 root      19   0 1105m 760m  16m S  0.7 74.2   5:20.51 java
  </code></pre>
  
  <p>Shouldn't the overall consumed memory (heap + PermGen) stay under what is specified using -Xmx? One of the problems this is causing is that I cannot shutdown the server using the shutdown script since it tries to spawn a JVM with 256MB of memory which fails because of it not being available.</p>