Java option 관련

정리차원에서 글 써본다.
java -server 옵션은 지난번에 썻고.
java 의 디폴트 initial heap size는 physical memory의 1/64 이다. maximum heap size는 physcal memory의 1/4 이다.

만약 physical memory가 4G이면, initial heap size는 62Mbyte이고 max heap size는 1G이다.

또한 GC 옵션은  UseParallelGC이다.



http://download.oracle.com/javase/6/docs/technotes/guides/vm/gc-ergonomics.html

1. On server-class machines running the server VM, the garbage collector (GC) has changed from the previous serial collector (-XX:+UseSerialGC) to a parallel collector (-XX:+UseParallelGC). You can override this default by using the -XX:+UseSerialGC command-line option to the java command.

2. On server-class machines running either VM (client or server) with the parallel garbage collector (-XX:+UseParallelGC) the initial heap size and maximum heap size have changed as follows.

   initial heap size:

   Larger of 1/64th of the machine's physical memory on the machine or some reasonable minimum. Before J2SE 5.0, the default initial heap size was a reasonable minimum, which varies by platform. You can override this default using the -Xms command-line option.

   maximum heap size:

   Smaller of 1/4th of the physical memory or 1GB. Before J2SE 5.0, the default maximum heap size was 64MB. You can override this default using the -Xmx command-line option.