https://github.com/jattach/jattach

JVM Dynamic Attach utility
https://github.com/jattach/jattach

Last synced: about 1 month ago
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JVM Dynamic Attach utility

• Host: GitHub
• URL: https://github.com/jattach/jattach
• Owner: jattach
• License: apache-2.0
• Created: 2016-03-29T13:00:43.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-09-05T20:43:13.000Z (3 months ago)
• Last Synced: 2024-11-06T00:52:01.877Z (about 1 month ago)
• Language: C
• Homepage: https://github.com/jattach/jattach/releases
• Size: 76.2 KB
• Stars: 971
• Watchers: 22
• Forks: 114
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
## 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/

[Supported commands](http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/812ed44725b8/src/share/vm/services/attachListener.cpp#l388):

 - **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](https://github.com/jattach/jattach/releases) page.

On some platforms, you can also [install](#installation) jattach with a package manager.

### Examples

#### Load native agent

    $ jattach  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  load instrument false "javaagent.jar=arguments"

#### List available jcmd commands 

    $ jattach  jcmd help -all

### Installation

#### Debian, Ubuntu

On Debian and Ubuntu, you can install `jattach` from the official repository:

    # apt install jattach

#### Alpine Linux

On Alpine Linux, you can install `jattach` package from the edge/community repository:

    # apk add --no-cache jattach --repository http://dl-cdn.alpinelinux.org/alpine/edge/community/

#### Archlinux

[jattach](https://aur.archlinux.org/packages/jattach/) package can be installed from [AUR](https://wiki.archlinux.org/index.php/Arch_User_Repository) using one of [AUR helpers](https://wiki.archlinux.org/index.php/AUR_helpers), e.g., `yay`:

    # yay -S jattach

#### FreeBSD

On FreeBSD, you can use the following command to install `jattach`:

    # pkg install jattach