replace code
ExtensionLoader<T> loader = (ExtensionLoader<T>) EXTENSION_LOADERS.get(type);
if (loader == null) {
EXTENSION_LOADERS.putIfAbsent(type, new ExtensionLoader<T>(type));
loader = (ExtensionLoader<T>) EXTENSION_LOADERS.get(type);
}
return loader;
to
return (ExtensionLoader<T>) EXTENSION_LOADERS.computeIfAbsent(type, k -> new ExtensionLoader<T>(type));