我正在學習一些JVM工具,如jstat,JMAP,jtack等。當我在命令行中鍵入jstat
,它具有以下消息的響應:-J選項在jstat中的含義是什麼?
Usage:
jmap [option] <pid>
(to connect to running process)
jmap [option] <executable <core>
(to connect to a core file)
jmap [option] [[email protected]]<remote server IP or hostname>
(to connect to remote debug server)
where <option> is one of:
<none> to print same info as Solaris pmap
-heap to print java heap summary
-histo[:live] to print histogram of java object heap; if the "live"
suboption is specified, only count live objects
-permstat to print permanent generation statistics
-finalizerinfo to print information on objects awaiting finalization
-dump:<dump-options> to dump java heap in hprof binary format
dump-options:
live dump only live objects; if not specified,
all objects in the heap are dumped.
format=b binary format
file=<file> dump heap to <file>
Example: jmap -dump:live,format=b,file=heap.bin <pid>
-F force. Use with -dump:<dump-options> <pid> or -histo
to force a heap dump or histogram when <pid> does not
respond. The "live" suboption is not supported
in this mode.
-h | -help to print this help message
-J<flag> to pass <flag> directly to the runtime system
的問題是,我很困惑與選項-J。
-J<flag> to pass <flag> directly to the runtime system
當我鍵入jstat -J-version
,它說
java version "1.6.0_22"
Java(TM) SE Runtime Environment (build 1.6.0_22-b04)
Java HotSpot(TM) 64-Bit Server VM (build 17.1-b03, mixed mode)
是什麼使用此選項又是什麼 「旗」 意味着什麼?
您是否考慮過諮詢[documentation](http://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html)? – EJP
@EJP我認爲這很明顯,他確實閱讀了文檔,因爲它在他的問題中有很好的記錄。 – Craig
@EJP我認爲'將直接傳遞給運行時系統'的幫助信息是該選項的官方說明,但我不明白這一點。因此,我用關鍵字'傳遞'直接搜索到谷歌,而不是'jstat',因此我得不到任何有價值的東西。在閱讀EJP提到的文檔後,相當清楚 - -J只是表示javaOption.Much謝謝。 –