JVM监控工具--jstat(虚拟机状态监控)
参考：http://docs.oracle.com/javase/6/docs/technotes/tools/share/jstat.html

class	Statistics on the behavior of the class loader.
compiler	Statistics of the behavior of the HotSpot Just-in-Time compiler.
gc	Statistics of the behavior of the garbage collected heap.
gccapacity	Statistics of the capacities of the generations and their corresponding spaces.
gccause	Summary of garbage collection statistics (same as -gcutil), with the cause of the last and current (if applicable) garbage collection events.
gcnew	Statistics of the behavior of the new generation.
gcnewcapacity	Statistics of the sizes of the new generations and its corresponding spaces.
gcold	Statistics of the behavior of the old and permanent generations.
gcoldcapacity	Statistics of the sizes of the old generation.
gcpermcapacity	Statistics of the sizes of the permanent generation.
gcutil	Summary of garbage collection statistics.
printcompilation	HotSpot compilation method statistics.

C:\Documents and Settings>jstat -gcutil -h2 2112 250 4
  S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000

C:\Documents and Settings>jstat -gcutil -t 2112 250 4
Timestamp         S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
         1239.2   0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
         1239.5   0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
         1239.7   0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
         1240.0   0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
C:\Documents and Settings>jstat -gcutil 2112 250 4
  S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000
  0.00   0.00  13.28   0.00  18.69      0    0.000     0    0.000    0.000