The client code has a "com.sun.awt.SecurityWarning" class which at some point in the past, JDK 6u10, was used as a kind of "public" API.

During development of jdk9 it was considered that this API is not supported and may be removed in the future: JDK-8051640.
In jdk11 this class was marked as "forRemoval = true" (see JDK-8205588) and can be dropped in 12.