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

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    0.000C:\Documents and Settings>jstat -gcutil -t 2112 250 4Timestamp         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    0.000C:\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