why MyClass.class exists in java and MyField.field isn't?

Question

Let\'s say I have:

class A {
    Integer b;
    void c() {}
}

Why does Java have this syntax: A.class, and doesn\'t have a syntax

Answer 1

I'm not sure if I fully understand your question. You are being unclear in what you mean by A.class syntax. You can use the reflections API to get the class from a given object by:

A a = new A()
Class c = a.getClass()

or

Class c = A.class;

Then do some things using c.

The reflections API is mostly used for debugging tools, since Java has support for polymorphism, you can always know the actual Class of an object at runtime, so the reflections API was developed to help debug problems (sub-class given, when super-class behavior is expected, etc.).

The reason there is no b.field or c.method, is because they have no meaning and no functional purpose in Java. You cannot create a reference to a method, and a field cannot change its type at runtime, these things are set at compile-time. Java is a very rigid language, without much in the way of runtime-flexibility (unless you use dynamic class loading, but even then you need some information on the loaded objects). If you have come from a flexible language like Ruby or Javascript, then you might find Java a little controlling for your tastes.

However, having the compiler help you figure our potential problems in your code is very helpful.