title: unable to set xmx beyond 4gb on system having 8gb RAM
body: <p>I need to set </p>
  
  <pre><code>ANT_OPTS=-Xms1024m -Xmx6144m -XX:PermSize=1024m -XX:MaxPermSize=1024m
  
  JAVA_OPTS=-Xms1024m -Xmx6144m -XX:PermSize=1024m -XX:MaxPermSize=1024m
  </code></pre>
  
  <p>I have a system with 8gb(recently upgraded from 4 gb)</p>
  
  <p>But once i set the ant opts to above said value I am not able to run any of my ant targets and I get the following error </p>
  
  <pre><code>[ERROR] Argument error: -Xmx6144m
  [ERROR] Specified maximum heap size (6144 MB) is larger than the address space on this platform (4 GB).
  [WARN ] -XX:PermSize=1024m is not a valid VM option. Ignoring
  [WARN ] -XX:MaxPermSize=1024m is not a valid VM option. Ignoring
  Could not create the Java virtual machine.
  </code></pre>
  
  <p>This indicates the Java that I have on my system</p>
  
  <pre><code>java version "1.6.0_20"
  Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
  Oracle JRockit(R) (build R28.1.0-123-138454-1.6.0_20-20101014-1351-windows-x86_64, compiled mode)
  </code></pre>
  
  <p>and I am running a Windows 7 on Intel Core 2 Duo 3Ghz processor and 8GB RAM.</p>
  
  <p><em>PS: I did Google for the error and it was one of my first such occurrences where I did not get any links pointing to the specific solution.</em> </p>