Gridlayout expands rows and columns

I am very new in the Java world and I am having the following issue, it is very simple but don't know what I am doing wrong.

Very simple, I create a container with a grid layout of 3x3, I put more than 9 elements and the grid rearranges to the elements in the grid and dosen't stay as a 3x3 gridlayout. I want it so stay as a 3x3 grid independently of the elements in it.

Please help.

enter image description here

public class InterfaceUno extends JFrame {

private static final long serialVersionUID = 1L;

public static InterfaceUno InterfacePrincipal;
private Container Content;  
private JSplitPane Split; 
private Button Botton1, Botton2, Botton3, Botton4, Botton5, Botton6, Botton7, Botton8, Botton9, Botton10, Botton11, Botton12, Botton13, Botton14, Botton15, Botton16, Botton17, Botton18, Botton19, Botton20, Botton21, Botton22;
private JPanel BottonPanel;

public static void main(String[] args) {
    // TODO Auto-generated method stub
    InterfacePrincipal = new InterfaceUno();
    InterfacePrincipal.setVisible(true);
    InterfacePrincipal.setResizable(false);
}

    private InterfaceUno() {

        ImageIcon img = new ImageIcon(this.getClass().getResource("icon.png"));
        this.setIconImage(img.getImage());

        Content=getContentPane();
        setSize(750,750);
        setTitle("InterfaceUno");
        Content.setBackground(Color.black);
        Content.setLayout(new BorderLayout());

        BottonPanel = new JPanel();
        BottonPanel.setLayout(new GridLayout(3,3));
    //  BottonPanel.setBorder(BorderFactory.createTitledBorder(null, "Statistics", TitledBorder.TOP,TitledBorder.CENTER, new Font("Lucida Calligraphy",Font.PLAIN,20), Color.ORANGE));

        Botton1 = new Button("Botton 1");
        Botton2 = new Button("Botton 2");
        Botton3 = new Button("Botton 3");
        Botton4 = new Button("Botton 4");
        Botton5 = new Button("Botton 5");
        Botton6 = new Button("Botton 6");
        Botton7 = new Button("Botton 7");
        Botton8 = new Button("Botton 8");
        Botton9 = new Button("Botton 9");
        Botton10 = new Button("Botton 10");
        Botton11 = new Button("Botton 11");
        Botton12 = new Button("Botton 12");
        Botton13 = new Button("Botton 13");
        Botton14 = new Button("Botton 14");
        Botton15 = new Button("Botton 15");
        Botton16 = new Button("Botton 16");
        Botton17 = new Button("Botton 17");
        Botton18 = new Button("Botton 18");
        Botton19 = new Button("Botton 19");
        Botton20 = new Button("Botton 20");
        Botton21 = new Button("Botton 21");
        Botton22 = new Button("Botton 22");

        Botton1.setBackground(Color.black);
        Botton1.setForeground(Color.white);
        //Botton1.addActionListener(new START());
//      Botton1.setPreferredSize(new Dimension(30,30));

        BottonPanel.add(Botton1);
        BottonPanel.add(Botton2);
        BottonPanel.add(Botton3);
        BottonPanel.add(Botton4);
        BottonPanel.add(Botton5);
        BottonPanel.add(Botton6);
        BottonPanel.add(Botton7);
        BottonPanel.add(Botton8);
        BottonPanel.add(Botton9);
        BottonPanel.add(Botton10);
        BottonPanel.add(Botton11);
        BottonPanel.add(Botton12);
        BottonPanel.add(Botton13);
        BottonPanel.add(Botton14);
        BottonPanel.add(Botton15);
        BottonPanel.add(Botton16);
        BottonPanel.add(Botton17);
        BottonPanel.add(Botton18);
        BottonPanel.add(Botton19);
        BottonPanel.add(Botton20);
        BottonPanel.add(Botton21);
        BottonPanel.add(Botton22);

        Content.add(BottonPanel);


    }

}