Oracle hotSpot

When the following flags are set:

   -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -Xloggc:filename
   

The Sun JVM produces the following garbage collection statistics:

   0.000: [GC 0.001: [DefNew: 32192K->511K(33152K), 0.0383176 secs] 
32192K->511K(101440K), 0.0385223 secs]
   1.109: [GC 1.110: [DefNew: 32703K->198K(33152K), 0.0344874 secs] 
32703K->697K(101440K), 0.0346844 secs]
   2.408: [GC 2.409: [DefNew: 32390K->403K(33152K), 0.0227843 secs] 
32889K->902K(101440K), 0.0231518 secs]
   

To include date and time information in GC logs for Sun JDK, use the "-XX:+PrintGCDateStamps Java™ argument.

Please see extensive Java information on http://www.oracle.com/technetwork/java/javase/tech/index-jsp-136373.html for examples of how to diagnose GC problems.