JVM introspection

Install

emisar pack install validates the pack and verifies its content hash before copying it into /etc/emisar/packs. The --hash below pins the install to the exact bytes on this page — a tampered copy is rejected. After install, reload the runner; it re-reads the catalog and advertises every action.

content hash: sha256:0a6dc0afb1b6993592fc43f0c60ce1c9369511bca17ef74e58a4fd9d8f1a7bfa

sudo emisar pack install java-jvm \
  --hash sha256:0a6dc0afb1b6993592fc43f0c60ce1c9369511bca17ef74e58a4fd9d8f1a7bfa \
  --dest /etc/emisar/packs

# Reload so the runner re-reads the catalog:
sudo systemctl reload emisar

• jvm.classloader_stats exec low

  jcmd VM.classloader_stats

• jvm.heap_dump exec critical

  jmap -dump:live (heap dump)

• jvm.heap_summary exec low

  jcmd GC.heap_info

• jvm.jcmd_gc_run exec medium

  jcmd <pid> GC.run

• jvm.jfr_dump exec medium

  Dump active JFR recording

• jvm.jfr_start exec medium

  Start a Java Flight Recording

• jvm.jfr_stop exec medium

  Stop active JFR recording

• jvm.jmap_histo_live exec medium

  jmap -histo:live (top 50)

• jvm.jstack exec low

  jstack -l (thread dump)

• jvm.jstack_blocked exec low

  jstack filtered to BLOCKED threads

• jvm.jstat_class exec low

  jstat -class

• jvm.jstat_gc exec low

  jstat -gc (10 samples)

• jvm.perfdata exec low

  jcmd PerfCounter.print

• jvm.thread_count exec low

  OS thread count for a JVM

• jvm.vm_flags exec low

  jcmd VM.flags

• jvm.vm_system_properties exec low

  jcmd VM.system_properties

• jvm.vm_uptime exec low

  jcmd VM.uptime