http://rensanning.iteye.com/blog/1545708?page=2#comments
http://www.iteye.com/topic/1124225
http://www.linuxeden.com/plus/view.php?aid=67067
From the source for OpenJDK I would say it is
const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
// This is useful for debugging but don't change the output the
// the customer sees.
const char* gc_cause_str = "Full GC";
if (is_system_gc && PrintGCDetails) {
gc_cause_str = "Full GC (System)";
}
I created a custom version of the Runtime class to record the thread name and stack trace to a file whenever Runtime.getRuntime().gc() was called. (System.gc() calls this) I found it useful in tracking down and removing such callers.
One place this happens is in sun.misc.GC class. The RMI will ask this class to ensure a GC has been performing in the last N seconds. If there has been no GC it triggers a full GC.
This only shows as a problem if you reduce the number of minor GCs. Ironicly it can mean you get more full GCs. ;)
I don't use RMI (except perhaps JConsole) So I have it set to a week. (Think the default is an hour)
-Dsun.rmi.dgc.server.gcInterval=604800000
-Dsun.rmi.dgc.client.gcInterval=604800000