Summary

Add a clear description of the expected behavior of using options "live" and "all" together for jmap.

Problem

jmap -histo and jmap -dump can accept "live" and "all" options together. The specification should describe clearly what is the expected behavior of using them together.

Solution

Add the description "live dump only live objects (takes precedence if both \"live\" and \"all\" are specified)" to help info of jmap -dump command.

and add "live count only live objects (takes precedence if both \"live\" and \"all\" are specified)" to help info of jmap -histo.

Specification

Updated specification:

Usage:
jmap -clstats <pid>
    to connect to running process and print class loader statistics
jmap -finalizerinfo <pid>
    to connect to running process and print information on objects awaiting finalization
jmap -histo[:[<histo-options>]] <pid>
    to connect to running process and print histogram of java object heap
jmap -dump:<dump-options> <pid>
    to connect to running process and dump java heap
jmap -? -h --help
    to print this help message

dump-options:
  live         dump only live objects (takes precedence if both "live" and "all" are specified)
  all          dump all objects in the heap (default if one of "live" or "all" is not specified)
  format=b     binary format
  file=<file>  dump heap to <file>

Example: jmap -dump:live,format=b,file=heap.bin <pid>

histo-options:
  live         count only live objects (takes precedence if both "live" and "all" are specified)
  all          count all objects in the heap (default if one of "live" or "all" is not specified)
  file=<file>  dump data to <file>
  parallel=<number>  parallel threads number for heap iteration:
                              parallel=0 default behavior, use predefined number of threads
                              parallel=1 disable parallel heap iteration
                              parallel=<N> use N threads for parallel heap iteration

Example: jmap -histo:live,file=/tmp/histo.data <pid>