Hello Jie Yu. You are correct that the only way to debug without starting
the Java program in debug mode with -agentlib:.... is to use the
SAPIDAttachingConnector,
and then you can only read information out of the VM - you can't modify
the state.
For JDK 7, we are investigating a feature we call 'attach on demand
debugging'
which would do just what you are asking for.
The 'SA' in SAPIDAttachingConnector stands for Serviceability Agent.
All the files under the hotspot/agent directory that you reference below
are part of the Serviceability Agent. You can find out more about the
SA here:
http://openjdk.java.net/groups/hotspot/docs/Serviceability.html#bsa
SA is also used by HotSpot engineers to debug HotSpot itself. The
files you mention under the hotspot/livejvm are used for that.
HTH
- jjh
Jie Yu wrote:
Hi,
I am a student from Fudan University, China. I am working on a project that
uses JPDA of JDK6. I want to debug a live java program that is not start with
any debug options (e.g. -agentlib:jdwp or -Xdebug). For this reason, I can
choose the SAPIDAttachingConnector. But the VirtualMachine object returned by
this connector's attach() method is 'read-only', meaning that I cannot modify
the state of the live java program. Is there any other options for me? I scan
the source tree of openjdk, and find that in
hotspot/agent/src/share/classes/sun/jvm/hotspot/livejvm, there are some related
source files. What are these files for? Are they related to my problem?
Best regards,
Jie Yu
