Open Source ETL framework [closed]

Answer 1

One of the most popular Java based ETL would be Talend.

Jaspersoft ETL is another one extended from Talend and has a nice eclipse based UI.

Answer 2

Another option is CloverETL. It is written in Java and there is an open source, LGPL version of its Engine. As well it has a free version of GUI called CloverETL Community.

It can process any of the indicated sources and connects to a number of databases, including MySQL.

Answer 3

I've used Kettle. It has its own GUI, but if you rather use the API to do the ETL yourself it's also supported. It has proved to be very useful to me and there are a few plugins already available for it.