The font code has an undesirable dependency on internal text classes that should be re-examined with a view to eliminating the dependency:

java.awt.font.StyledParagraph -> sun.text.CodePointIterator (java.base)
java.awt.font.TextLayout -> sun.text.CodePointIterator (java.base)
java.awt.font.TextLine -> sun.text.CodePointIterator (java.base)
sun.font.FontResolver -> sun.text.CodePointIterator (java.base)

Note that the font code is the only consumer of sun.text.CodePointIterator and a simple first step is to just move this class to sun.font.

A better solution is to look at the new codePoints() methods in CharSequence to see if that could be used instead. It requires understanding the usage in the font code to see if this is feasible or not.