title: What is the concurrent mark-sweep generation in the heap?
body: <p>In the following output, what is the concurrent mark-sweep generation?</p>
  
  <pre><code>par new generation   total 24512K, used 12082K [0x00007fb3b9420000, 0x00007fb3bac20000, 0x00007fb3bac20000)
   eden space 24448K,  49% used [0x00007fb3b9420000, 0x00007fb3b9fec808, 0x00007fb3bac00000)
   from space 64K,   0% used [0x00007fb3bac10000, 0x00007fb3bac10000, 0x00007fb3bac20000)
   to   space 64K,   0% used [0x00007fb3bac00000, 0x00007fb3bac00000, 0x00007fb3bac10000)
  concurrent mark-sweep generation total 8364032K, used 233100K [0x00007fb3bac20000, 0x00007fb5b9420000, 0x00007fb5b9420000)
  concurrent-mark-sweep perm gen total 98304K, used 72031K [0x00007fb5b9420000, 0x00007fb5bf420000, 0x00007fb5bf420000)
  </code></pre>
  
  <p>I understand eden, from, to and perm gen, but what is "concurrent mark-sweep generation"?</p>