Class::newInstance() doesn't have any parameters (also, it's deprecated: better to use getConstructor() or getDeclaredConstructor() and call newInstance() on it).

Also, the generic agreement on your calls to makeAndPrint is failing.

This does what you wanted:

jshell> class Foo { }
|  modified class Foo

jshell> class Bar extends Foo { }
|  modified class Bar

jshell> class Baz extends Foo { }
|  modified class Baz

jshell> class Main {
   ...>   public static void main(String[] args) {
   ...>     makeAndPrint(Foo.class);
   ...>     makeAndPrint(Bar.class);
   ...>     makeAndPrint(Baz.class);
   ...>   }
   ...>
   ...>   public static void makeAndPrint(Class<? extends Foo> klass) {
   ...>     try {
   ...>       Object o = klass.newInstance();
   ...>       System.out.println("Created: " + o.toString());
   ...>     } catch (Exception e) {
   ...>       System.err.println("Failed: " + klass);
   ...>     }
   ...>   }
   ...> }
|  created class Main

jshell> Main.main(new String[]{})
Created: REPL.$JShell$11$Foo@6a4f787b
Created: REPL.$JShell$12$Bar@7d9d1a19
Created: REPL.$JShell$13$Baz@39c0f4a

On Sat, 6 Feb 2021 at 20:56, Luís Oliveira <luismbo@gmail.com> wrote:

On Sat, 6 Feb 2021 at 16:29, Manfred Bergmann <manfred.bergmann@me.com> wrote:
> But this is kind of also possible in i.e. Java where you can say:
> Foo.class.newInstance() which uses reflection and is not normally used.
> But is effectively similar to make-instance `foo.

 My Java is getting rustier and rustier, but maybe you can tell me why
the following program doesn't compile:

class Foo { }
class Bar extends Foo { }
class Baz extends Foo { }

class Main {
  public static void main(String[] args) {
    makeAndPrint(Foo.class);
    makeAndPrint(Bar.class);
    makeAndPrint(Baz.class);
  }

  public static void makeAndPrint(Class<Foo> klass) {
    try {
      Object o = klass.newInstance(klass);
      System.out.println("Created: " + o.toString());
    } catch (Exception e) {
      System.err.println("Failed: " + klass);
    }
  }
}

The rough equivalent in Common Lisp would be:

(defclass foo () ())
(defclass bar (foo) ())
(defclass baz (foo) ())

(mapcar #'make-instance '(foo bar baz))

Luís

--

He who binds to himself a joy
Doth the winged life destroy
But he who kisses the joy as it flies
Lives in Eternitys sun rise

- William Blake