Well,
my previous Message still waits for being approved... so I can't answer my own thread.
But I solved the problem anyway by patching it myself.
Steps:
1) extract "xercesImpl.jar"
2) open /META-INF/services/javax.xml.datatype.DatatypeFactory
3) exchange "org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl" by " com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFacto ryImpl "
4) whip it all up again to xercesImpl.jar
==> that's all -> no more Java crashes.
Correct prefs.xml is created here (still the path has this sick name, but it works):
~/.java/.userPrefs/_!'8!cg"n!#4!bw"w!'`!bg"t!'8!b!"l!':!d@"s!'`!cw!u!'@!}@"0!'%!dw"h!()!cg"p!'8!cg==
Contents is
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE map SYSTEM "I CAN NOT CREATE LINKS WITHIN THIS POST">
<map MAP_XML_VERSION="1.0">
<entry key="automatic_update_check" value="false"/>
<entry key="first_launch" value="1111111111111"/>
</map>
Best regards,
BuildOnC