The calculations should be initialized in the JAppletRobotArm.java -
because this is the main applet. Do I need a main() method in an
Applet?

So what I want to do is to initialize Calculations calculation, and use
methods from this class for instance in: private JButton getJButton() {

Thanks once again for the swift reply.

This is the code (removed comments) as it is in JAppletRobotArm.java
===================================================
import javax.swing.JPanel;
import javax.swing.JApplet;
import javax.swing.JTabbedPane;
import javax.swing.JButton;
public class JAppletRobotArm extends JApplet {
    private static final long serialVersionUID = 2621050794148530944L;
    private JPanel jContentPane = null;
    private JTabbedPane jTabbedPane = null;
    private JPanel jPanelOptions = null;
    private JPanel jPanelGraphs = null;
    private JPanel jPanelStatistics = null;
    private JButton jButton = null;
    private JButton jButtonNextGen = null;
    private JPanel jPanelRobotArm1 = null;
    private JPanel jPanelRobotArm2 = null;

    public JAppletRobotArm() {
        super();
        Calculations calculation = new Calculations();
    }

       private JTabbedPane getJTabbedPane() {
        if (jTabbedPane == null) {
            jTabbedPane = new JTabbedPane();
            jTabbedPane.setBounds(new java.awt.Rectangle(1,5,492,342));
            jTabbedPane.addTab("Graphs", null, getJPanelGraphs(), null);
            jTabbedPane.addTab("Options", null, getJPanelOptions(), null);
            jTabbedPane.addTab("Statistics", null, getJPanelStatistics(), null);
        }
        return jTabbedPane;
    }

    private JPanel getJPanelOptions() {
        if (jPanelOptions == null) {
            jPanelOptions = new JPanel();
            jPanelOptions.setLayout(null);
        }
        return jPanelOptions;
    }

    private JPanel getJPanelGraphs() {
        if (jPanelGraphs == null) {
            jPanelGraphs = new JPanel();
            jPanelGraphs.setLayout(null);
            jPanelGraphs.add(getJButton(), null);
            jPanelGraphs.add(getJButtonNextGen(), null);
            jPanelGraphs.add(getJPanelRobotArm1(), null);
            jPanelGraphs.add(getJPanelRobotArm2(), null);
        }
        return jPanelGraphs;
    }

    private JPanel getJPanelStatistics() {
        if (jPanelStatistics == null) {
            jPanelStatistics = new JPanel();
        }
        return jPanelStatistics;
    }

    private JButton getJButton() {
        if (jButton == null) {
            jButton = new JButton();
            jButton.setBounds(new java.awt.Rectangle(142,6,104,25));
            jButton.setText("Start/pause");
            jButton.addPropertyChangeListener(new
java.beans.PropertyChangeListener() {
                public void propertyChange(java.beans.PropertyChangeEvent e) {
                    if ((e.getPropertyName().equals("enabled"))) {
                        System.out.println("propertyChange(enabled)"); // TODO
Auto-generated property Event stub "enabled"
                    }
                }
            });
        }
        return jButton;
    }

    private JButton getJButtonNextGen() {
        if (jButtonNextGen == null) {
            jButtonNextGen = new JButton();
            jButtonNextGen.setBounds(new java.awt.Rectangle(8,5,130,27));
            jButtonNextGen.setText("Next Generation");
        }
        return jButtonNextGen;
    }

    private JPanel getJPanelRobotArm1() {
        if (jPanelRobotArm1 == null) {
            jPanelRobotArm1 = new JPanel();
            jPanelRobotArm1.setPreferredSize(new java.awt.Dimension(200,200));
            jPanelRobotArm1.setSize(new java.awt.Dimension(200,200));
            jPanelRobotArm1.setLocation(new java.awt.Point(7,33));
        }
        return jPanelRobotArm1;
    }
    private JPanel getJPanelRobotArm2() {
        if (jPanelRobotArm2 == null) {
            jPanelRobotArm2 = new JPanel();
            jPanelRobotArm2.setBounds(new java.awt.Rectangle(208,33,200,200));
            jPanelRobotArm2.setPreferredSize(new java.awt.Dimension(200,200));
        }
        return jPanelRobotArm2;
    }

    public void init() {
        this.setSize(500, 400);
        this.setContentPane(getJContentPane());
        //this.calculation = new Calculations();
    }

    private JPanel getJContentPane() {
        if (jContentPane == null) {
            jContentPane = new JPanel();
            jContentPane.setLayout(null);
            jContentPane.add(getJTabbedPane(), null);
        }
        return jContentPane;
    }

}  //  @jve:decl-index=0:visual-constraint="0,7"

On Tue, 06 Dec 2005 14:25:51 +0100, Hendrik Maryns
<hendrik_maryns@despammed.com> wrote, quoted or indirectly quoted
someone who said :

did he not say he was writing an JApplet? You need a public init.

Applets don't decide their size. HTML does.

this should not be necessary unless you are doing something very
peculiar.

When I hear someone referred to as "Jamie", I would be shocked to find
that they are male.  Obviously, I feel differently about "Chris".  ;)