When customer tries to use Preferences.node (myStr) , where myStr has
"." , a directory with junk name is created in
$HOME/.java/.userPrefs. From the JS bug : 4678154 we found that " ."
is not a valid character that. But there is no API documentation which
provides the list of supported characters and specifies that "." is not
a valid character .
 
The following link talks about the preference API , but there is no
information about the supported characters.
http://java.sun.com/j2se/1.5.0/docs/guide/preferences/index.html

We would like javasoft to provide the list of supported characters for
this API . This would help the user to be aware of supported characters