一、jps 查询正在运行的虚拟机进程。
-m输出虚拟机进程启动时传递给main()函数的参数
-l输出进程执行的主类的全名
-v输出虚拟机进程启动时的JVM参数
二、jinfo 查看虚拟机配置参数信息
三、jstack 生成java虚拟机当前时刻的线程快照
-F：当正常输出请求不被响应时，强制输出线程栈堆。
-l：显示关于锁的附加信息。
-m：显示本地方法栈
四、jmap 生成虚拟机内存转储快照
Usage:
jmap [option] <pid>
(to connect to running process)
jmap [option] <executable <core>
(to connect to a core file)
jmap [option] [server_id@]<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
-clstats to print class loader 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五、jhat 分析 Jmap 产生的堆复制文件
jhat -J-Xmx512m heap.dmp