private static Configuration instance() {
if (config == null) {
try {
// Default values build into war file, this is last prio used if no of the other sources override this
boolean allowexternal = Boolean.getBoolean(new PropertiesConfiguration(ExternalRaGuiConfiguration.class.getResource("/" + PROPERTIES_FILENAME)).getString(PROPERTY_CONFIGALLOWEXTERNAL, "false"));
config = new CompositeConfiguration();
PropertiesConfiguration pc;
// Only add these config sources if we allow external configuration
if (allowexternal) {
// Override with system properties, this is prio 1 if it exists (java -Dscep.test=foo)
config.addConfiguration(new SystemConfiguration());