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But can you pass classes around as objects after they're loaded? Do they have a value beyond their identifier?

• dminor 17y ago
  Yes, although Java's reflection is somewhat of a pain in the ass and limited in many ways. But you can take a Class object and call newInstance(), and it will invoke the class's no-arg constructor.
  • duskwuff 17y ago
    Moreover, reflection is less of a language feature and more of a very low-level library feature. In ObjC, one can write Class c = [SomeRandomClass class]; id thingy = [[c alloc] init]; but Java won't let you do the equivalent: Class c = SomeRandomClass; Object x = new c;
    • vlisivka 17y ago
      Class c = SomeRandomClass.class; Object x=c.newInstance();
      • duskwuff 17y ago
        Yes, but that's making use of runtime magic (the Class class) which isn't used outside metaprogramming.
• pvg 17y ago
  Yep, you can pass them around, they do have values, in fact, they can have different values for the same type sometimes. This has been the case since well before Java even had reflection - having them around is fairly central to the Java dynamic loading and security model.
• lucifer 17y ago
  When you define a class, say "Foo", instances of Foo are Foo objects. "Foo", itself, is an instance of a class named "Class" which is a direct descendent of the class "Object". In Java's type system, classes are 'first class objects': http://en.wikipedia.org/wiki/First-class_object http://en.wikipedia.org/wiki/First-class_object