Default class with public constructor - why?

Question

Noticed some code that had a class with package-level access and a public constructor - wondered what the benefit/use of that would be... Thanks!

Answer 1

GarudaJava wrote:
Noticed some code that had a class with package-level access and a public constructor - wondered what the benefit/use of that would be... Thanks!If the class itself doesn't need to be exposed, but it implements some interface, and is assumed to have a public no-arg consturctor, it could be created reflexively. This is a contrived situation, but it's the only one I can think of in Java where that'd be useful.
package foo;
class Foo implements SomeInterface {
  public Foo() {
package factory;
class Factory {
  public static SomeInterface create(Class<? extends SomeInterface> clazz) { // not sure if I got the generics right, but they're incidendtal to the example
    return clazz.newInstance();
package foo;
import factory.Factory;
public class Bar {
  public void bar() {
    SomeInterface si = Factory.create(Foo.class);
    si.doStuff();
}Like I said, pretty contrived, and I can't think of a real-world use case that matches it offhand, but structurally it'd look something like that.
You could also maybe imagine that the factory package might do more than just create and return an instance. It might create it and use that SomeInterface type for its own ends.