Could error check this code

Question

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.lang.Math.*;
import javax.swing.*;
public class YValue extends JApplet implements ActionListener
    JTextField xminField;
    JTextField xmaxField;
    JTextField iterField;
    JTextArea xyvalArea;
    JLabel xminLabel;
    JLabel xmaxLabel;
    JLabel iterLabel;
    JLabel xyvalLabel;
    JButton calcButton;
    public void init()
        setBounds(500, 500, 500, 500);
        Container pane = getContentPane();
        pane.setLayout(null);
        xminField           = new JTextField();
        xminField.setBounds(70, 10, 60, 25);
        xmaxField           = new JTextField();
        xmaxField.setBounds(70, 40, 60, 25);
        iterField          = new JTextField();
        iterField.setBounds(70, 70, 60, 25);
        xyvalArea          = new JTextArea();
        xyvalArea.setEditable(true);
        xyvalArea.setBounds(10, 130, 200, 200);
        JScrollPane scrollPane = new JScrollPane(xyvalArea);
        scrollPane.setBounds(10, 130, 200, 200);
        pane.add(scrollPane);
        xminLabel           = new JLabel("X - Min:");
        xminLabel.setBounds(10, 10, 60, 25);
        xmaxLabel           = new JLabel("X - Max:");
        xmaxLabel.setBounds(10, 40, 60, 25);
        iterLabel          = new JLabel("Iteration:");
        iterLabel.setBounds(10, 70, 60, 25);
        xyvalLabel          = new JLabel("X, Y - Values:");
        xyvalLabel.setBounds(10, 100, 100, 25);
        calcButton          = new JButton("Calculate:");
        calcButton.addActionListener(this);
        calcButton.setBounds(150, 40, 90, 20);
        pane.add(xminLabel);
        pane.add(xminField);
        pane.add(xmaxLabel);
        pane.add(xmaxField);
        pane.add(iterLabel);
        pane.add(iterField);
        pane.add(xyvalLabel);
        pane.add(xyvalArea);
        pane.add(calcButton);
        setContentPane(pane);
          setVisible( true );
    public void actionPerformed(ActionEvent e)
          xyvalArea.setText("");
          // get values from fields and convert to float
          String xminStr      = xminField.getText();                         // get input as string
          int xmin           = Integer.parseInt(xminStr);               // convert to integer
          float xminFl      = Float.valueOf(xminStr).floatValue();     // convert to float
          String xmaxStr      = xmaxField.getText();                         // get input as string
          int xmax           = Integer.parseInt(xmaxStr);               // convert to integer
          String iterStr      = iterField.getText();                         // get input as string
          int iter           = Integer.parseInt(iterStr);               // convert to integer
          float iterFl      = Float.valueOf(iterStr).floatValue();     // convert to float
          // create variables for purposes of calculating distance between two X values
          int neg      = -1;                                                  // create variable with value minus one
          neg           = (xmin * neg);                                        // multiply minimum X value by -1 to get positive value
          int length      = (neg + xmax);                                        // add minimum and maximum X values to get distance between them
          float xmin2Fl = (xminFl * xminFl);                              // minimum X value squared reamins constant
          // loop which lasts the distance between two X values
          for(int i = 0; i<=length; i = i + iter)
               float xmin2tmp      = (xminFl * xminFl);                    // current x2
               float xmin3tmp     = (xmin2Fl - xmin2tmp);                    // minimum x2 minus current x2
               double y           = Math.sqrt(xmin3tmp);                    // get square root of x2 - x*x
               String output      = ("(" + xminFl +", "+ y + ")");     // output (x, y)
               xyvalArea.append(output + "\n");                         // append to textArea with a new line
               xminFl = (xminFl + iterFl);                               // move X value to next iterval point
}the scroll bar wont work at all and a white box the size of the text area appears in the top left corner when i run the applet every so often...
any help would be great.
cheers

Answer 1

this is whats happening..
i copied .java file to new location, compiled and ran, still screws up every few times i run it.
what is:
http://img191.imageshack.us/img191/2439/whatis7sb.jpg
what should:
http://img191.imageshack.us/img191/5854/whatshud7md.jpg