Java HotSpot Virtual Machine

Hi,

I can not figure out what makes VM to run Full GC from time to time like in the listing below...

Any ideas ?

thanks,
Alex

JRE 1.5.0_06, Linux 2.6.9

java -Xms300M -Xmx300M -XX:ThreadStackSize=100 -Xss100K -server -XX:NewSize=80M -XX:MaxNewSize=80M -XX:SurvivorRatio=2 -XX:TargetSurvivorRatio=80 -XX:PermSize=8M -XX:+DisableExplicitGC -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -verbose:gc -Xloggc:gc.log -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC



2069.493: [Full GC {Heap before gc invocations=79:
def new generation total 61440K, used 59230K [0x9be40000, 0xa0e40000, 0xa0e40000)
eden space 40960K, 99% used [0x9be40000, 0x9e637258, 0x9e640000)
from space 20480K, 89% used [0x9fa40000, 0xa0c20618, 0xa0e40000)
to space 20480K, 0% used [0x9e640000, 0x9e640000, 0x9fa40000)
tenured generation total 225280K, used 26314K [0xa0e40000, 0xaea40000, 0xaea40000)
the space 225280K, 11% used [0xa0e40000, 0xa27f2a10, 0xa27f2c00, 0xaea40000)
compacting perm gen total 8192K, used 5258K [0xaea40000, 0xaf240000, 0xb2a40000)
the space 8192K, 64% used [0xaea40000, 0xaef62bb0, 0xaef62c00, 0xaf240000)
No shared spaces configured.
2069.493: [DefNew: 59230K->13381K(61440K), 0.0525370 secs] 85544K->44677K(286720K)Heap after gc invocations=80:
def new generation total 61440K, used 13381K [0x9be40000, 0xa0e40000, 0xa0e40000)
eden space 40960K, 0% used [0x9be40000, 0x9be40000, 0x9e640000)
from space 20480K, 65% used [0x9e640000, 0x9f351700, 0x9fa40000)
to space 20480K, 0% used [0x9fa40000, 0x9fa40000, 0xa0e40000)
tenured generation total 225280K, used 31295K [0xa0e40000, 0xaea40000, 0xaea40000)
the space 225280K, 13% used [0xa0e40000, 0xa2ccfe90, 0xa2cd0000, 0xaea40000)
compacting perm gen total 8192K, used 5258K [0xaea40000, 0xaf240000, 0xb2a40000)
the space 8192K, 64% used [0xaea40000, 0xaef62bb0, 0xaef62c00, 0xaf240000)
No shared spaces configured.
}
, 0.0530170 secs]

---------------------------------------

2469.687: [Full GC {Heap before gc invocations=106:
def new generation total 61440K, used 55607K [0x9be40000, 0xa0e40000, 0xa0e40000)
eden space 40960K, 99% used [0x9be40000, 0x9e63d9c8, 0x9e640000)
from space 20480K, 71% used [0x9e640000, 0x9f4903f0, 0x9fa40000)
to space 20480K, 0% used [0x9fa40000, 0x9fa40000, 0xa0e40000)
tenured generation total 225280K, used 37794K [0xa0e40000, 0xaea40000, 0xaea40000)
the space 225280K, 16% used [0xa0e40000, 0xa3328868, 0xa3328a00, 0xaea40000)
compacting perm gen total 8192K, used 5269K [0xaea40000, 0xaf240000, 0xb2a40000)
the space 8192K, 64% used [0xaea40000, 0xaef657c0, 0xaef65800, 0xaf240000)
No shared spaces configured.
2469.687: [DefNew: 55607K->17641K(61440K), 0.0471880 secs] 93401K->55435K(286720K)Heap after gc invocations=107:
def new generation total 61440K, used 17641K [0x9be40000, 0xa0e40000, 0xa0e40000)
eden space 40960K, 0% used [0x9be40000, 0x9be40000, 0x9e640000)
from space 20480K, 86% used [0x9fa40000, 0xa0b7a748, 0xa0e40000)
to space 20480K, 0% used [0x9e640000, 0x9e640000, 0x9fa40000)
tenured generation total 225280K, used 37794K [0xa0e40000, 0xaea40000, 0xaea40000)
the space 225280K, 16% used [0xa0e40000, 0xa3328868, 0xa3328a00, 0xaea40000)
compacting perm gen total 8192K, used 5269K [0xaea40000, 0xaf240000, 0xb2a40000)
the space 8192K, 64% used [0xaea40000, 0xaef657c0, 0xaef65800, 0xaf240000)
No shared spaces configured.
}
, 0.0476750 secs]