Java generics – class or class

I am writing a program that will dynamically create class instances based on user input using java reflection (i.e. class. Forname()) One requirement is that the instance created by my program must extend a class I define, called someclass My question is: should I use bounded generics to store this class type, extend someclass > or simple unbounded generic classes? I found that some java books say that class is one of the good habits of using unbounded wildcards, but I wonder if this applies to my program

If you find that my problem is not clear enough or you need some information, please feel free to let me know

Solution

You should use class to extend someclass > because it is generic

When you call class Forname, check someclass class. Isassignable comes from the new class Otherwise, you should throw an illegalargumentexception or ClassCastException

Edit: alternatively, calling assubclass (someclass. Class) will do this for you

For example:

public SomeClass instantiate(String name)
  throws ClassNotFoundException,InstantiationException,illegalaccessexception {

    Class<?> raw = Class.forName(name);

    //throws ClassCastException if wrong
    Class<? extends SomeClass> generic = raw.asSubclass(SomeClass.class);

    // do what you want with `generic`

    return generic.newInstance();
}