It appears that in a server environment CollationParsedRuleBuilder is unable to
properly load the invuca.dat resource. This is probably because the returned
input stream is not null, because the code is using the class loader for the
string class, and so is looking for a system resource and not in the icu4j jar
file. You'd think this would throw an exception, but it returns a null
InputStream and BufferedInputStream happily accepts it in its constructor.
Change CollationParsedRuleBuilder to use it's own class loader!
(Check other uses of getResourceAsStream in ICU4J too).