sclass LASClassLoader extends InMemoryClassLoader is ILASClassLoader {
  new Map<S, Class> definedClasses;
  Lock lock = lock();
  
  *(ClassLoader parent) { super(parent); }
  *(Class parent) { super(parent.getClassLoader()); }
  
  public Class<?> defineLASClass(S name, IF0<byte[]> generateClass) {
    lock lock;
    
    try {
      ret loadClass(name);
    } catch (ClassNotFoundException e) {
      print("Generating class " + name);
      ret defineAClass(name, generateClass!);
    }
  }
}

Began life as a copy of #1034296