Reflection & Nested Classes

[Ian A. Mason]

I'm designing an application and was thinking of using reflection, but
a simple experiment failed. Here it is. I'm reading Dale Green's
chapter in the Java Tutorial, and I copy his simplest example of
constructing an object using a no arg constructor, and modify it
slightly to reflect the types of things I'm interested in
(java.awt.Shape) and in particular the 2D versions:

import java.lang.reflect.*;
import java.awt.*;
import java.awt.geom.*;

class SampleNoArg {

public static void main(String[] args) {
Rectangle2D.Float r =
(Rectangle2D.Float)createObject("java.awt.geom.Rectangle2D.Float");
System.out.println(r.toString());
}

static Object createObject(String className) {
Object object = null;
try {
Class classDefinition = Class.forName(className);
object = classDefinition.newInstance();
} catch (InstantiationException e) {
System.out.println(e);
} catch (IllegalAccessException e) {
System.out.println(e);
} catch (ClassNotFoundException e) {
System.out.println(e);
}
return object;
}
}


and I discover it can't find the class by that name. I also notice that
nested classes don't seem to be mentioned in the refection API
(i.e they don't qualify as members). So should I give up, or is there
a way to make such beasts using reflection.

 

[Chris Smith]

and I discover it can't find the class by that name. I also notice that
nested classes don't seem to be mentioned in the refection API
(i.e they don't qualify as members). So should I give up, or is there
a way to make such beasts using reflection.

This is one of those ugly cases where implementation detail shines
through. Try "java.awt.geom.Rectangle2D$Float".

--
www.designacourse.com
The Easiest Way to Train Anyone... Anywhere.

Chris Smith - Lead Software Developer/Technical Trainer
MindIQ Corporation

 

[Tony Morris]

and I discover it can't find the class by that name. I also notice that

nested classes don't seem to be mentioned in the refection API
(i.e they don't qualify as members). So should I give up, or is there
a way to make such beasts using reflection.

You can access nested classes using:
java.lang.Class#getClasses
java.lang.Class#getDeclaredClasses

--
Tony Morris
(BInfTech, Cert 3 I.T.)
Software Engineer
(2003 VTR1000F)
Sun Certified Programmer for the Java 2 Platform (1.4)
Sun Certified Developer for the Java 2 Platform