title: JVM heap stuck at 2g even when started with -Xmx 3G
body: <p>We have a weird issue with a java process.
  It was started with -Xmx3G , and at some point it started throwing :</p>
  
  <pre><code>java.lang.OutOfMemoryError: Java heap space
  </code></pre>
  
  <p>Checking the GC logs around the time the error is thrown, the heap size seems stuck at 2G ?</p>
  
  <pre><code>...
  12893.533: [Full GC 2248110K-&gt;2248109K(2315776K), 0.4723440 secs]
  212894.006: [Full GC 2248110K-&gt;2248109K(2315776K), 0.4823290 secs]
  212894.490: [Full GC 2248110K-&gt;2248110K(2315776K), 0.4642130 secs]
  212894.955: [Full GC 2248114K-&gt;2248112K(2315776K), 0.4866180 secs]
  ...
  </code></pre>
  
  <p>What are the possible reasons that could explain this ?</p>