NonStop Server for Java 5.1 Programmer's Reference

-XX:+UseParallelGC
Specifies a parallel garbage collector. If you specify this option, the JVM exits with the error:
-XX:+UseParallelGC option is not supported on this platform.
-XX:+UseParNewGC
Specifies a parallel garbage collection. This option is disabled. If you specify this option, the JVM exits with
the error: -XX:+UseParNewGC option is not supported on this platform.
-XX:+UseAdaptiveSizePolicy
Specifies an adaptive size policy. This option applies only for a parallel collector and, therefore, is disabled.
If you specify this option, the JVM exits with the error: -XX:+UseAdaptiveSizePolicy option is not
supported on this platform.
-XX:+AggressiveHeap
Obtains the platform resources and configures the heap layout accordingly, uses parallel collector, and
enables AdaptiveSizePolicy option. This option applies only for a parallel collector and, therefore, is
disabled. If you specify this option, the JVM exits with the error: -XX:+AggressiveHeap option is not
supported on this platform.
-XX:GCHeapFreeLimit=space-limit
Specifies the lower limit on the amount of space freed during a garbage collection in percentage of the
maximum heap.
-XX:GCTimeLimit=time-limit
Specifies the upper limit on the amount of time spent in garbage collection in percent of total time.
Also, the following flags of the Garbage Collector Ergonomics technology for a parallel collector are not
supported. These specify performance goals for the application.
-XX:MaxGCPauseMillis=nnn
-XX:GCTimeRatio=nnn
Concurrent Low-Pause Collector
A concurrent low-pause collector is for tenured generation. This collector does most of the collection concurrently
with the application execution. This collector divides the collection into different phases and does some phases
concurrently with the application execution and others in "stop the world" mode. This collection technique does
not perform well as the default collector when the phases of the collection cannot run concurrently with the
application thread. This garbage collector, therefore, is disabled in NonStop Server for Java 5.1.
The following java command options that specify a concurrent low-pause collector are not valid for
NonStop Server for Java 5.1:
-XX:+UseConcMarkSweepGC
Specifies using the concurrent mark-sweep garbage collector. If you specify this option, the
JVM exits with the error: -XX:+UseConcMarkSweepGC option is not supported on this
platform.
-Xconcgc
Enables a concurrent mark-sweep garbage collector. This option is disabled. If you specify this
option, the JVM exits with the error: -Xconcgc option is not supported on this platform.