mappingsLock.readLock().unlock();
}
if(prefixes == null){
ServiceReference[] refs = getSortedProviderReferences();
for(int i=0;prefixes == null && i<refs.length;i++){
NamespacePrefixProvider provider = getService(refs[i]);
if(provider != null){
prefixes = provider.getPrefixes(namespace);
}
}
}
return prefixes == null ? Collections.EMPTY_LIST:prefixes;
}