java's inheritance property doubt

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Java

I have written 2 simple programs in java. These are as follows :

public class simple{
    public static void main(String[] args){
        System.out.println("Hello World");
    }
}

import javax.swing.JOptionPane;
public class simple1 extends JOptionPane{
    public static void main(String[] args){
        JOptionPane.showMessageDialog(null,"Hello World");
    }
}

Yes . these are working just fine with the appropriate output. Now,

when I execute the following statements in my command prompt(to get the content of class file),

javap simple
Compiled from "simple.java"
public class simple extends java.lang.Object{
    public simple();
    public static void main(java.lang.String[]);
}

javap simple1
Compiled from "simple1.java"
public class simple1 extends javax.swing.JOptionPane{
    public simple1();
    public static void main(java.lang.String[]);
}

Now these are the things which I don't understand:

I) Books (Deitel and Deitel) say that java.lang.Object is automatically inherited in EVERY program , but the second class file doesn't show it? If it does then java should support multiple inheritance. There is some kind of a hidden mechanism. What is it?

II) What is the parent class in java?