I already have a shell that has components of a calculator and would like to put an icon of my own at the top left corner of my calculator, I have tried many code like these but they aren't yielding

Java Code:
super("CIT Calculator");
   JPanel p = new JPanel(new GridLayout(5,4,1,1)); //The grid will have 5 rows
   setIconImage(Toolkit.getDefaultToolkit().getImage("muklogo.gif"));
   
   
   // Add components to frame
   // constracting the screen
   Container c = getContentPane();
   c.setLayout(new FlowLayout());
   t1 = new JTextField( 50 );
   c.add( t1 );


// setting size of the shell
  setSize(600,200);
  setDefaultCloseOperation(EXIT_ON_CLOSE);
  setVisible(true);