/*     Why Mother Didn't Teach You Everything About Java Either ...

                      Sequel By Chuck Liang
         

   Mother: What kind of program are you working on, and what programming
           language are you using, sweetheart?

   Man:    I'm using Java now, just like you said I should.  I'm writing
           a program that keeps track of bank accounts. And I'm making all
           my instance variables PRIVATE. Your balance is safe with me!

   Mother: Uh oh, I was afraid this was going to happen ...  There's
           something I never told you about Java.

   Man:    What? Not again! You promised! What didn't you tell me about
           Java?

   Mother: That there's a package called reflection which will give you
           access to all private elements of a class, and even list them
           for you.

   Man:    Motherhacker!  What the hell!  That's terrible!  Why bother!
           Why didn't you tell me the truth?!

   Mother: Private variables and methods are designed for encapsulation,
           not for security.  But I had to invent a story that was easy
           for you to believe, like when I told you that santa claus won't
           come to our house unless you ate your vegetables.

   Mother: But perhaps this notion of privacy represents a naive
           understanding of the kind of program organization that's
           required of modern software.  Sometimes we require the
           flexibility of changing the abstraction ...

   Man:    What are you talking about ma?  That there's no santa claus?

   Mother: Of course there is!  Just eat your vegetables.
*/

import java.lang.reflect.*;

class account
{
    private double balance;  ///// PRIVATE VARS CAN'T BE SEEN BY BAD PEOPLE?!
    public account(double b) { balance=b; }
    public void withdraw(double amt) 
    { if (amt>0 && amt<balance) balance -= amt; 
	if (amt>1000000 && Math.random()<.000000000001) //the rich get richer
	  winprize(); // you won you lucky hacker!
    }
    public double inquiry() { return balance; }

    private void winprize() { balance += 10000; } // only call internally!
}//account

public class mother
{
    public static void main(String[] argv) throws Exception
    {
        account youraccount = new account(1000);
	Field bal = account.class.getDeclaredField("balance");
	bal.setAccessible(true);

	double yourbalance = bal.getDouble(youraccount);
	System.out.println("your 'private' balance was "+yourbalance);

	bal.setDouble(youraccount,0);  // balance set to 0.  Motherhacker!
	System.out.println("but now it is "+youraccount.inquiry());


	// what kind of "private" methods sucker bank won't allow me to call?
	Method[] F = account.class.getDeclaredMethods();
        System.out.println("all methods of account class:");
	for(Method m:F) {System.out.println(m.getName());}

	Method alwayswin = account.class.getDeclaredMethod("winprize");
	alwayswin.setAccessible(true);
	for(int i=0;i<100;i++) alwayswin.invoke(youraccount);

	System.out.println("But you're extremely lucky and your balance is now "+youraccount.inquiry());
    }//main
}