Reference to java.awt.dnd.peer.DragSourceContextPeer prevents testing with JDK 13 (probably JDK 9 and later) #15
Description
The test ExampleConcreteClass references java.awt.dnd.peer.DragSourceContextPeer which is non-exported, thus not API, and thus not accessible from JDK 9 on.
Since the specifically referenced class seems to fulfill no other purpose than being a random class reference, I suggest to replace it with java.awt.dnd.DragSourceContext for now.
I am already preparing a Pull Request for this.