NonStop Server for Java 4.2 Programmer's Reference

-XX:MaxPermSize
Sets the maximum size for the permanent generation. The default value for MaxPermSize is 32 MB. The
initial size of the permanent generation PermSize option is ignored.
Note: At initialization time, the maximum size of the combined young and tenured generations and
the maximum size of permanent generation are allocated.
Implementation of Garbage Collector Types
The default garbage collectors in NonStop Server for Java 4 are
Copying collector for the young generation
●
Mark-sweep collector for the tenured generation●
NonStop Server for Java 4 uses these garbage collectors because they are the most efficient on the
NonStop system. A summary of garbage collector implementations appears in the table below. Paragraphs that
follow discuss various implementations to help you understand performance issues.
Collector Type Implementation Status
Copying collector
Default collector for the young
generation
Mark-sweep collector
Default collector for the tenured
generation
Parallel collector
Disabled
Concurrent low-pause
collector
Disabled
Incremental low-pause
collector
Allowed
Parallel Collector
The parallel collector (or throughput collector) uses the parallel version of the young generation collector. The
parallel collector is disabled in NonStop Server for Java 4 because this collector applies only for Symmetric
Multiprocessing (SMP) type machines. NonStop systems are not SMP type machines.
The following java command options that specify a parallel collector or apply to a parallel collector are not valid
for NonStop Server for Java 4:
-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