Class and static method Class.forName() drive me crazy

Question

this code doesn\'t compile. I\'m wondering what I am doing wrong:

private static Importable getRightInstance(String s) throws Exception {
 Class

        

Answer 1

Try:

Class klaz = Class.forName(s).asSubclass(Importable.class);

Here are some snippets to illustrate the problems:

Class klazz = String.class; // doesn't compile!
// "Type mismatch: cannot convert from Class to Class"

However:

Class klazz = String.class; // compiles fine!

So for an interface, you definitely need the upper-bounded wildcard. The asSubclass is as suggested by doublep.

API links

• Class asSubclass(Class clazz)
  • Casts this Class object to represent a subclass of the class represented by the specified class object. Checks that that the cast is valid, and throws a ClassCastException if it is not. If this method succeeds, it always returns a reference to this class object.

Related questions

• What is the difference between and ?

See also

• Java Tutorials/Generics/Subtyping
• More fun with wildcards