At http://www.bluemontsw.com/unoofc/unoofc.html I've made available a freeware Java class framework for programming LibreOffice Writer, Calc, Impress, Draw, and chart documents without direct use of UNO or the XInterface API. The framework classes abstract and encapsulate UNO and API functionality, and application code involves objects and instance methods of framework classes rather than the interface methods of the XInterface API. An application programmer does not need to know the API interfaces or UNO. The framework currently provides much basic XInterface functionality, including charts, but not all functionality. See the information at http://www.bluemontsw.com/unoofc/unoofc.html.