jattach
JVM Dynamic Attach utility
The utility to send commands to a JVM process via Dynamic Attach mechanism.
All-in-one jmap + jstack + jcmd + jinfo functionality in a single tiny program.
No installed JDK required, works with just JRE. Supports Linux containers.
This is the lightweight native version of HotSpot Attach API
https://docs.oracle.com/javase/8/docs/jdk/api/attach/spec/
- load : load agent library
- properties : print system properties
- agentProperties : print agent properties
- datadump : show heap and thread summary
- threaddump : dump all stack traces (like jstack)
- dumpheap : dump heap (like jmap)
- inspectheap : heap histogram (like jmap -histo)
- setflag : modify manageable VM flag
- printflag : print VM flag
- jcmd : execute jcmd command
Download
Binaries are available on the Releases page.
On some platforms, you can also install jattach with a package manager.
Examples
Load native agent
$ jattach <pid> load <.so-path> { true | false } [ options ]
Where true means that the path is absolute, false -- the path is relative.
options are passed to the agent.
Load Java agent
Java agents are loaded by the special built-in native agent named instrument,
which takes .jar path and its arguments as a single options string.
$ jattach <pid> load instrument false "javaagent.jar=arguments"
List available jcmd commands
$ jattach <pid> jcmd "help -all"
Installation
FreeBSD
On FreeBSD, you can use the following command to install jattach package:
$ pkg install jattach
Alpine Linux
On Alpine Linux, you can use the following command to install jattach package from the edge/community repository:
$ apk add --no-cache jattach --repository http://dl-cdn.alpinelinux.org/alpine/edge/community/
Archlinux
jattach package can be installed from AUR using one of AUR helpers, e.g., yay:
$ yay -S jattach
Debian Linux
On Debian Linux, you can use the following command to install jattach from the official repository:
$ apt install jattach
Packages are provided for bullseye (stable), bookworm (testing) and sid (unstable).