Drawing a picture within JFrame when I've already created a JFrame

Question

Hi everyone,
I was wondering if you could help me out with this problem I'm getting. I'm creating a program to simulate an 'elevator.' When first creating the project I created a brand new 'Java GUI Form' : 'JFrame Form'. From here I went on to drag-and-drop various command buttons and labels to create the user interface (the 'inside' of an elevator). Here is where my question comes in. On the very left of my interface I want to have the program draw a simulation of a box (the elevator) moving up and down with the 'floor numbers' the user pushes. However i don't know how to access the coding of the jFrame object that I created through the design editor so i can input the coding.
First Question: What do i have to 'write' that would force that box to print into the current JFrame?
Second Question: What Code (and where do i put it) essentially 'locks' the JFrame from being resized?

Answer 1

Here, maybe by putting this it might help you recognize what i'm trying to say. The code i'm trying to put in is:
JFrame window = new JFrame ("Drawing");
        window.setBounds(200,200,700,500);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setVisible(true);
        Container contentPane = window.getContentPane();
        contentPane.setBackground(new Color(125, 125, 125));
        Graphics g = contentPane.getGraphics();* This is a portion of the code
When run, this program creates a NEW JFRAME WINDOWS, i'm trying to make it run inside an already existing JFrame, whose variable Name i dont know how to find.