Could not find it? Can you?

Question

When I run this program I can see the message and I can input number but when methods returns d I can not see the value of d at all. I get a message on the applet like this:
Start: applet not initialized
import java.awt.Container;
// Java extension packages
import javax.swing.*;
public class Assignment extends JApplet {
// initialize applet by obtaining user input and creating GUI
public void init()
String s1 = null;
String s2 = null;
String s3 = null;
String FirstNumber;
int option;
// create JTextArea to display results
JTextArea outputArea = new JTextArea();
      JOptionPane.showMessageDialog
         (null,"Enter: '1' to find out HYPOTENUSE \n\n Enter: '2' to find out OPPOSTIE \n\n Enter: '3' to find out ADJACENT ");
// obtain user input
FirstNumber =JOptionPane.showInputDialog("Please Enter your option: ");
option = Integer.parseInt( FirstNumber );
if(option==1) {
s1 = JOptionPane.showInputDialog(
"Please Enter OPPOSITE " );
s2 = JOptionPane.showInputDialog(
"Please Enter ADJECENT " );
else if(option==2)
s2 = JOptionPane.showInputDialog(
"Please Enter ADJECENT " );
s3 = JOptionPane.showInputDialog(
"Please Enter HYPOTENUSE " );
else if(option==3)
s1 = JOptionPane.showInputDialog(
"Please Enter OPPOSITE" );
s3 = JOptionPane.showInputDialog(
"Please Enter HYPOTENUSE" );
else
JOptionPane.showMessageDialog(null,"You have entered wrong code try again please ");
// convert user input to double values
double number1 = Double.parseDouble( s1 );
double number2 = Double.parseDouble( s2 );
double number3 = Double.parseDouble( s3 );
// call method maximum to determine largest value
double pythagoras = maximum(option, number1, number2, number3 );
if(option==1) {
// display numbers and maximum value
outputArea.setText( "HYPOTENUSE is: " + pythagoras);
if(option==2)
outputArea.setText("OPPOSITE is: " + number1);
if(option==2)
outputArea.setText( "ADJACENT is: " + number2);
// get the applet's GUI component display area
Container container = getContentPane();
// attach outputArea to Container c
container.add( outputArea );
} // end method init
public double maximum(int a, double x, double y, double z )
double b,c,d=0;
if(a==1) {
b=x*x;
c=y*y;
z=b+c;
d=Math.sqrt(z);
if(a==2) {
b=z*z;
c= y*y;
x=b-c;
d=Math.sqrt(x);
if(a==3) {
b=z*z;
c=x*x;
y=z-x;
d=Math.sqrt(y);
return d;
}

Answer 1

Thanks for the advice I have fixed the problems but still I am a bit curious how can I not show the third input in each selection ( Please enter 0) but get the third input valid?
kind regards,
import java.awt.Container;
// Java extension packages
import javax.swing.*;
public class Assignment extends JApplet {
// initialize applet by obtaining user input and creating GUI
public void init()
String s1 = null;
String s2 = null;
String s3 = null;
String FirstNumber;
int option;
// create JTextArea to display results
      JOptionPane.showMessageDialog
         (null,"Enter: '1' to find out HYPOTENUSE \n\n Enter: '2' to find out OPPOSITE \n\n Enter: '3' to find out ADJACENT ");
// obtain user input
FirstNumber =JOptionPane.showInputDialog("Please Enter your option: ");
option = Integer.parseInt( FirstNumber );
if(option==1) {
s1 = JOptionPane.showInputDialog(
"Please Enter OPPOSITE " );
s2 = JOptionPane.showInputDialog(
"Please Enter ADJECENT " );
s3 = JOptionPane.showInputDialog(
"Please Enter 0 " );
else if(option==2)
s2 = JOptionPane.showInputDialog(
"Please Enter ADJECENT " );
s3 = JOptionPane.showInputDialog(
"Please Enter HYPOTENUSE " );
s1 = JOptionPane.showInputDialog(
"Please Enter 0 " );
else if(option==3)
s1 = JOptionPane.showInputDialog(
"Please Enter OPPOSITE" );
s3 = JOptionPane.showInputDialog(
"Please Enter HYPOTENUSE" );
s2 = JOptionPane.showInputDialog(
"Please Enter 0 " ); 
else
JOptionPane.showMessageDialog(null,"You have entered wrong code try again please ");
// convert user input to double values
double number1 = Double.parseDouble( s1 );
double number2 = Double.parseDouble( s2 );
double number3 = Double.parseDouble( s3 );
// call method maximum to determine largest value
double pythagoras = maximum(option, number1, number2, number3 );
JTextArea outputArea = new JTextArea();
if(option==1) {
// display numbers and maximum value
outputArea.setText( "HYPOTENUSE is: " + pythagoras);
if(option==2)
outputArea.setText("OPPOSITE is: " + pythagoras);
if(option==3)
outputArea.setText( "ADJACENT is: " + pythagoras);
// get the applet's GUI component display area
Container container = getContentPane();
// attach outputArea to Container c
container.add( outputArea );
} // end method init
public double maximum(int a, double x, double y, double z )
double b,c,d=0;
if(a==1) {
b=x*x;
c=y*y;
z=b+c;
d=Math.sqrt(z);
if(a==2) {
b=z*z;
c= y*y;
x=b-c;
d=Math.sqrt(x);
if(a==3) {
b=z*z;
c=x*x;
y=b-c;
d=Math.sqrt(y);
return d;
}