title: Whether the free space of JVM can be used by other applications
body: <p>Suppose the maximum size of a JVM heap is 2GB (-Xmx2048m -Xms100m), we find that the peak <em>used</em> usage of this heap is 1GB and the peak <em>committed</em> usage is 1.2GB after it finishes. So, my question is whether the free space (2GB - 1.2GB) can be consumed by other applications while the JVM is running.</p>
  
  <p>I think the free space cannot be used by others but I'm not sure currently: The operating system reserves 2GB free space before the JVM runs. The reserved space may not be consumed by other applications though the JVM cannot use it up. </p>