SAB 6.1 does not work with JDK 13

Just report.
Older version than 6.1 works with JDK 13 on Mac.
After installing 6.1, I got a build error.

I installed JDK 1.8 and set JDK 1.8 as JDK location on SAP.
I could successfully build and sign apk.

We only support JDK 8, as per the documentation.