Q:

Java Stack.peek() to objects

I am attempting to use a stack to put objects in a stack. I have a Pixel class that has a simple getX function that returns a variable defined in the constructor. When I use the stack.peek().getX(); it says that it cannot find the symbol for .getX();   
Stack stack = new Stack();
Pixel first = new Pixel(colorX,colorY);

stack.push(first);

int x = stack.peek().getX();

Am I using the peek function wrong? Or do I have my Pixel class setup incorrectly?
public class Pixel {
private int x, y , count = 0;

Pixel(int x_in, int y_in)
{
    x = x_in; 
    y = y_in;
}

public int getX(){return x;}
public int getY(){return y;}

A:

It is because you are using a raw Stack, instead of Stack<Pixel> that you get this error.  A raw stack is essentially equivalent to Stack<Object>, so when you call peek() it returns Object and not Pixel.  
Even though the runtime type may be Pixel, method resolution happens at compile time and Object has no getX() method.

