Hi,
There should be no issues if you implement it properly.
Always remember that in Java singletons are singletons per ClassLoader, and whenever you redeploy an app, a new ClassLoader is created. So, if you build an application that is redeploy-friendly, you have to handle the lifecycle of the application and release everything that the singleton has. If you fail to do this, you will end up with some leaks.
Regards,
-lg