title: options for G1 garbage collectors not available?
body: <p><a href="http://www.oracle.com/technetwork/java/javase/tech/g1-intro-jsp-135488.html" rel="nofollow">http://www.oracle.com/technetwork/java/javase/tech/g1-intro-jsp-135488.html</a> seems to be the official docs for the G1 garbage collector.</p>
  
  <p>There are two options mentioned:</p>
  
  <ul>
  <li>-XX:+G1ParallelRSetUpdatingEnabled </li>
  <li>-XX:+G1ParallelRSetScanningEnabled</li>
  </ul>
  
  <p>When configuring tomcat to use G1 with these options, catalina.log shows up</p>
  
  <pre><code>Unrecognized VM option '+G1ParallelRSetUpdatingEnabled'
  Could not create the Java virtual machine.
  </code></pre>
  
  <p>My JVM is</p>
  
  <pre><code>$ java -version
  java version "1.6.0_26"
  Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
  Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)
  </code></pre>
  
  <p>and</p>
  
  <pre><code>JAVA_OPTS="-server -Djava.awt.headless=true -Xmx3G -Xss512k -XX:MaxPermSize=1G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:+G1ParallelRSetUpdatingEnabled -XX:+G1ParallelRSetScanningEnabled" 
  </code></pre>
  
  <p>Any hints why -XX:+G1ParallelRSetScanningEnabled does not work?</p>