Skip navigation.
Downloads | Product Documentation | Support

Using JRockit JDK

# Using jstat with BEA JRockit

The JVM Statistics Monitoring Tool, jstat, attaches to a Java virtual machine and collects and logs performance statistics as specified by the command line options. This tool is developed by Sun Microsystems Inc. and it is included in the installation package of BEA JRockit. For a complete description on how jstat works, please refer to: http://java.sun.com/j2se/1.5.0/docs/tooldocs/share/jstat.html. This appendix lists differences in the output when running the tool with BEA JRockit.

# Statistics Options and Output

The following table lists all available statistical options, statOption, when using BEA JRockit. The tables that follow, summarize the columns that jstat outputs for each statOption.

statOption | Displays
--- | ---
`-class` | Statistics on the behavior of the class loader.
`-compiler` | Statistics of the behavior of the JRockit compiler.
`-gc` | Statistics of the behavior of the garbage collected heap.
`-gcpause` | Statistics of garbage collection pauses.
`-printjit` | Statistic on the latest JIT compiler operations.
`-printopt` | Statistic on the latest optimizing compiler operations.

### -class statOption

Column | Description
--- | ---
`Loaded` | Number of classes loaded.
`Bytes` | Number of Kbytes loaded.
`Unloaded` | Number of classes unloaded.
`Bytes` | Number of Kbytes unloaded.

### -compiler statOption

Column | Description
--- | ---
`Compiled` | Number of compilation tasks performed.
`Jitted` | Number of JIT compilation tasks performed.
`Optimized` | Number of optimization compilation tasks performed.
`Time` | Time spent performing compilation tasks.
`TotalTimeJit` | Time spent performing JIT compilation tasks.
`TotalTimeOpt` | Time spent performing optimizing compilation tasks.

### -printjit statOption

Column | Description
--- | ---
`Jitted` | Number of JIT compilation tasks performed.
`TotalTimeJit` | Time spent performing JIT compilation tasks.
`LastJitMethod` | The last method compiled by the JIT.

### -printopt statOption

Column | Description
--- | ---
`Optimized` | Number of optimization compilation tasks performed.
`TotalTimeOpt` | Time spent performing optimizing compilation tasks.
`LastOptMethod` | The last method compiled by the optimizing compiler.

### -gc statOption

Column | Description
--- | ---
`HeapSize` | Heap size (KB).
`NurserySize` | Nursery size (KB).
`UsedHeapSize` | Used heap size (KB).
`YC` | Number of young generation collections.
`OC` | Number of old generation collections.
`YCTime` | Young generation garbage collection time (s).
`OCTime` | Old generation garbage collection time (s).
`GCTime` | Total garbage collection time (s).
`YCPauseTime` | Young generation pause time (s).
`OCPauseTime` | Old generation pause time (s).
`PauseTime` | Total pause time (s).
`Finalizers` | Number of pending finalizers.

### -gcpause statOption

Column | Description
--- | ---
`YC` | Number of young generation collections.
`OC` | Number of old generation collections.
`YCPauseTime` | Young generation pause time (s).
`OCPauseTime` | Old generation pause time (s).
`PauseTime` | Total pause time (s).