Overview

astack is a JVM TI agent that allows capturing Java stack traces of all threads in a JVM, similar to jstack, but without requiring the JVM to reach a safepoint. This allows debugging and monitoring without impacting the running application, which is important because reaching a safepoint may take many seconds when the system is under heavy load.

The agent listens on a TCP port and returns a new thread dump whenever a client connects, allowing easy remote monitoring.

Building

make JAVA_HOME=/path/to/jdk

Usage

Run Java with the agent added as a JVM argument, specifying the port number for the agent to listen on:

-agentpath:/path/to/libastack.so=port=2000

Alternatively, if modifying the Java command line is not possible, the above may be added to the JAVA_TOOL_OPTIONS environment variable.