Starting a Java agent after program start

java javaagents
Paul Keeble picture Paul Keeble · Aug 14, 2009 · Viewed 18k times · Source

Is it possible to insert a javaagent after virtual machine start from within the same VM?

Lets say for example we have an agent in a jar myagent.jar with the appropriate meta data set-up and an agentmain method already implemented. Now the users program calls an API call which should result in the insertion of the agent so that it can redefine the classes.

Can it be done and how?

Answer

Alan Cabrera picture Alan Cabrera · Dec 18, 2010

https://web.archive.org/web/20141014195801/http://dhruba.name/2010/02/07/creation-dynamic-loading-and-instrumentation-with-javaagents/ has a great example of how to write an agent as well as how to start one on the fly.

Related questions

Tutorials about javaagents

I'd like to learn something about javaagents, but researching is not easy. Most of result refers to JADE. I know java agent can mean two things: An agent programmed in Java being an incarnation of the agent concept of distributed …

Read More
Adding -javaagent to Tomcat 6 server, where do I put it and in what format?

I´m trying to install an application health monitoring application that can monitor J2EE web transactions and I need to put a javaagent into my Tomcat somehow but am not clear on exactly how to do this, I am …

Read More
How to put classes for javaagent in the classpath

I am trying to develop a javaagent that would instrument code with help of asm-4. For now I'm stucked with a pretty basic problem, the classloader for the javaagent doesn't see asm dependencies and therefor fails. Do I have to …

Read More