Prerequisites: Forms 9.0. Matter: where's dissapeared the StringComparator.class from f90all.jar!

I don't know exactly all the java versions having this problem related to Forms 9.0, but i am pretty certain that java 6 is. 
The thing is that nasty class is in another archive, share.jar, the one who can be founded under $ORACLE_HOME/jlib
I recommend you to work clean, something like this:

mkdir ~/test
cd ~/test
mkdir share
mkdir f90all

copy the two archives under its everyone folder

cd share
cp $ORACLE_HOME/forms90/java/share.jar
jar -xvf share.jar
cd ../f90all
cp $ORACLE_HOME/forms90/java/f90all.jar
jar -xvf f90all.jar

(i assume that your java bin executables are traceable by  PATH)

find the /oracle/bali/share/sort/StringComparator.class  file under share director and copy to the same named place under f90all folder.

cp ../share//oracle/bali/share/sort/StringComparator.class ../f90all///oracle/bali/share/sort/

Now u have to repackage again your upgraded class. First, be aware, mind the f90all.jar file, not to be arround, because the archiver might include it either in the archive. Also, delete the folder META-INF prior to repackage.

cd ~/test/f90all
jar -cvf  ~/test/f90all.jar *

And now all you have to do is signing the whole thing:

$ORACLE_HOME/forms90/webutil/sign_webutil.sh ~/test/f90all.jar
cp ~/test/f90all.jar $ORACLE_HOME/forms90/java

Et voila! The error vanished!