java agent based reloading

[claudegex]

Can anyone provide more information about the new feature on the server tab called "java agent based reloading". I gave it a short try and it reloaded properly my classes. But I'm wondering if this is a tc server feature and which functionality is provided with it.

Is there any documentation about it?

thanks
Claude

[Andy Clement]

Hi Claude,

The Java agent based reloading isn't only usable under tc Server, it is a general approach, but we've spent most of our time testing under tc Server. *Currently* we package it as part of the SpringSource Tool Suite, but that may change over time.

I don't think I've written down the feature list (or limitation list) anywhere actually, so let me give you some idea here. (I did talk about it at SpringOne and JavaOne last year). Regular 'hot code replace' allows you to change the bodies of methods/constructors. With the agent you can do:
- add/delete methods themselves
- add/delete fields
- add/delete constructors
- change annotations on those things
- change annotations on the type declarations

The main limitation right now is that it doesn't allow you to alter the hierarchy of a type, you can't change the set of interfaces you implement or your superclass.

Hope thats useful,

cheers
Andy
---
Andy Clement
SpringSource

[claudegex]

Hi Andy

Thanks for your answer! Therefore this feature is really new isn't it?

Okay, I've found the vm arguments in the tc Server run configuration:

-javaagent:"C:\springsource\sts-2.5.2.RELEASE\plugins\com.springsource.sts.server.tc.reloading_2.5.2.201101081000-RELEASE\lib\springloaded-0.5.1.jar" -noverify

I would appreciate if you could answer the following questions:

• Will this feature be turned into a commercial tool or is it intended to stay free to use?
• Is there a plan for further development?
• Will there be framework support such as done by JRebel?

Thanks
Claude

[Andy Clement]

Hi Claude,

> Will this feature be turned into a commercial tool or is it intended to stay free to use?

Likely to remain free (although I'm not sure I'm qualified to answer this definitively!), not sure if STS will always be the ship vehicle though. Our current focus around the STS/tcServer dev experience means it is a nice way to ship it right now whilst we work out the kinks.

> Is there a plan for further development?

Yep, it is actively under development, it is now working for groovy code and the next release will be doing more with grails reloading.

> Will there be framework support such as done by JRebel?

Yep, if we want to support the kinds of apps users deploy on tc Server we need support for informing the frameworks about changes (e.g. spring/hibernate).

cheers
Andy

[claudegex]

Thank you Andy for the quick response.
Looking forward to see this tool evolve.

Claude

[electricthought]

doesnt work for me.
How to change to another classloader?