code: @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
      if (!loadedClassFiles) {
        classFileMap = extractClassFileMap();
        loadedClassFiles = true;
      }
  
      if (classFileMap == null) {
        throw new ClassNotFoundException(name);
      }
  
      String internalName = name.replace('.', '/');
      CompiledClass compiledClass = classFileMap.get(internalName);
      if (compiledClass == null) {
        throw new ClassNotFoundException(name);
      }
  
      // Make sure the class's package is present.
      String pkg = compiledClass.getPackageName();
      if (getPackage(pkg) == null) {
        definePackage(pkg, null, null, null, null, null, null, null);
      }
  
      byte[] bytes = compiledClass.getBytes();
      return defineClass(name, bytes, 0, bytes.length);
    }
docs: Looks up classes in GWT's compilation state.