I know it may be resolved. As I've been searching for this and found a suggested resolution in the related bug
ROO-2151. I'm planning to migrate from windows to linux environment. In windows we have been using 1.1.5.RELEASE without this issue i.e when closing roo console in windows this is not happening. But when i moved same roo version including my addons (I've even changed the same version of java I was using in windows, but the linux release: jdk1.6.0_45) For a linux environmet (I'm using Centos 6.7 distro). Im getting this weird exception when exiting roo console. Except for this bug, everything else seems to be working ok. So I don't know if this Can not affect us for the further development of next projects by just ignoring this or if anyone else had reproduced the same scenario please share if any workaround has got of this.
Note: I've been researching more for this problem and have realized that I'm getting the same error in windows environment when trying to uninstall the addon. I've also updated to 1.2.5 version in linux environment including my addons with no luck (it is assumed that since 1.2.3 release the fix is included)