How to Load class object from source project ? How to use 'UrlClassLoader'?

Hi, 

I'm trying to invoke an API and this API invokes ‘Class.forname()’，then I got a 'ClassNotFoundException' .

Here is a similar post，but it doesn't work for me:

https://intellij-support.jetbrains.com/hc/en-us/community/posts/115000615544-Intellij-Plugin-Load-class-object-from-source-project

My code:

List<URL> urls = new ArrayList<>();
pluginModule.getAllIdeaModules().values().forEach(
        module -> {
            try {
                urls.add(VfsUtilCore.virtualToIoFile(CompilerModuleExtension.getInstance(module).getCompilerOutputPath()).toURI().toURL());
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
        }
);
ClassLoader original = Thread.currentThread().getContextClassLoader();
UrlClassLoader cl=UrlClassLoader.build().parent(original).useCache().urls(urls).allowBootstrapResources().get();

ClassLoaderUtil.runWithClassLoader(cl,()-> invokeApi()); //get ClassNotFoundException
ClassLoaderUtil.runWithClassLoader(cl,()->Class.forName("myProject.class.fqcn"));//get ClassNotFoundException

Is there anything wrong with my code？Or are there other ways to achieve to load class object from source code into plugin?