Im currently trying to establish a connection from my Android app to a MySQL server running on my raspberry pi.
I added the library to android studio correctly by ad
CTA = China Type Approval, this is something that Mediatek adds in Android for testing purpose.
Your error is happening in DriverManager.getConnection() that probably uses okhttp, apache-http or Socket class in Android's libcore to do its requests.
Mediatek patched these libraries for adding a control of HTTP requests. It tries to load dynamically some methods defined in /system/framework/mediatek-cta.jar but it is probably absent or not accessible on your android device's file system.
I see 5 solutions :
As I encountered the same message once, I also was misled by it firstly. However, it turned out that you can not open a Socket or other network connection on the main thread (see https://developer.android.com/training/basics/network-ops/connecting#intro-net-ops). This may also be the problem in your case.
This message itself only seems to be an information for testing purposes as vhamon pointed out.