import javax.swing.JOptionPane;

// This is an example illustrating inheritance and ploymorphism using Java class Object
public class Example5A {
    
    public Example5A() {
        String out = "";
        Object A = new Object();
        out += "A refers to an Object. A.toString() is: ";
        out += A.toString() + "\n"; // Since A refers to a Object object this will call
        // the Object toString()
        // out += A.length(); will not compile since A is an Object variable and
        // length() is not a member of Object
        A = new String("Sample String"); // A superClass varable can be assigned any of it's subclasses
        // So an Object variable can be assigned any class object
        out += "A now refers to a String. A.toString() is: ";
        out += A.toString() + "\n"; // Since A refers to a String object now this will call
        // the String toString(). This illustrates polymorphism
        // out += A.length(); will not compile since A is an Object variable and
        // length() is STILL not a member of Object
        int length = ((String)A).length(); // A superClass variable can be cast to any of it's subclasses
        // so an Object variabel can be cast to any class and
        // the compiler will not complain. Since A refers to a
        // String object here a runtime error will NOT occur
        A = 37;
        out += "A now refers to an Integer. A.toString() is:  ";
        out += A.toString() + "\n"; // polymorphism again
        JOptionPane.showMessageDialog(null,out);
        length =  ((String)A).length(); // An Object variable can be cast to any class
        // so the compiler will not complain. Since A refers to an
        // Integer object here a RUNTIME ERROR WILL occur
    } // end Example5A()
    
    public static void main(String[] args) {
        new Example5A();
    } // end main
    
} // end Example5A