[This information is extracted from 4181917 and enhanced]

Install the patch providing Euro currency support on Solaris 2.6 - see:
/net/sunsoftpatch/patches/temporary/T106842-01
If you don't have them yet, this also requires the following patches:
/net/sunsoftpatch/patches/temporary/T106841-01
/net/sunsoftpatch.eng/patches/patchdb/unbundled/openwin/3.6/105633-11

Reboot your machine, choose the de.ISO8859-15 locale from the login screen.

Remove all font.properties files from your home directory, place the attached file font.properties.ISO8859_15_FDIS file there.

Run the attached application EuroGUI, using the command line option -Dfile.encoding=ISO8859_15_FDIS to work around bug 4171977.

You should see a variety of AWT components using different fonts each displaying a string that includes the Euro character. In reality, the Euro character is not displayed in TextArea and TextField. Also, the fonts in the other components all look the same.

The following errors appear on the console:
Font specified in font.properties not found [-*-helvetica-medium-r-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-courier-medium-r-normal--*-%d-*-*-m-*-iso8859-15]
Font specified in font.properties not found [-*-courier-medium-o-normal--*-%d-*-*-m-*-iso8859-15]
Font specified in font.properties not found [-*-courier-medium-o-normal--*-%d-*-*-m-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-bold-o-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-medium-r-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-medium-o-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-bold-r-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-courier-medium-r-normal--*-%d-*-*-m-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-bold-o-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-times-medium-i-normal--*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-medium-o-normal-sans-*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-times-roman-r-normal--*-%d-*-*-p-*-iso8859-15]
Font specified in font.properties not found [-*-helvetica-bold-r-normal-sans-*-%d-*-*-p-*-iso8859-15]