question: private static boolean checkFont ( String fontName , String newName , String testString , boolean force ) { boolean displayable = true ; Font f = UIManager . getFont ( fontName ) ; if ( f != null && ! newName . equalsIgnoreCase ( f . getName ( ) ) ) { if ( ! GUIUtils . canDisplay ( f , testString ) || force ) { f = new Font ( newName , f . getStyle ( ) , f . getSize ( ) ) ; if ( GUIUtils . canDisplay ( f , testString ) ) UIManager . put ( fontName , f ) ; else displayable = false ; } } else if ( f != null ) { displayable = GUIUtils . canDisplay ( f , testString ) ; } else { displayable = false ; } return displayable ; }
target:  Updates the font of a given fontName to be newName.