try {
stream = ModelExtensionDefinitionHelper.class.getClassLoader().getResourceAsStream(fileName);
final Properties props = new Properties();
props.load(stream);
return new UnmodifiableProperties(props);
} catch (final IOException e) {
throw new IllegalStateException(TeiidI18n.errorReadingMedMetaclassMappings.text(fileName, e.getLocalizedMessage()), e);
} finally {
if (stream != null) {
try {