title: Full GC - Sun JVM frequency of run
body: <p>In JDK 1.6 : I see that full GC has been run but the old generation and perm gen space is not used completely - question is as per my understanding FGC only runs when old gen or perm gen is full - I am not able to understand why it has run even though usage % is low?.</p>
  <p>See output of jstat -gcutil below:</p>
  <pre>
    S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
   0.00  82.14  51.17  13.78  26.43    219   19.347     1    0.131   19.479
  
     S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
   82.14   0.00   9.12  13.92  26.66    222   19.771     1    0.131   19.902
  
     S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
   82.14   0.00  11.07   9.07  24.15    230   20.166     2    1.851   22.017
  </pre>
  <p>My min/max heap is 1024M and min and max permGen space is defined as 768M.</p>