Wednesday, 22 September 2010

Getting the super class using reflection in java

Because the Java programming language supports inheritance, an application such as a class browser must be able to identify superclasses. To determine the superclass of a class, you invoke the getSuperclass method. This method returns a Class object representing the superclass, or returns null if the class has no superclass. To identify all ancestors of a class, call getSuperclass iteratively until it returns null.
The program that follows finds the names of the Button class's ancestors by calling getSuperclass iteratively.
import java.lang.reflect.*;
import java.awt.*;

class SampleSuper {

public static void main(String[] args) {
Button b = new Button();
printSuperclasses(b);
}

static void printSuperclasses(Object o) {
Class subclass = o.getClass();
Class superclass = subclass.getSuperclass();
while (superclass != null) {
String className = superclass.getName();
System.out.println(className);
subclass = superclass;
superclass = subclass.getSuperclass();
}
}
}
The output of the sample program verifies that the parent of Button is Component, and that the parent of Component is Object:
java.awt.Component
java.lang.Object

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