Having trouble with an else statement.........

Question

I am having trouble figuring out what to do with this else statement error.........I can't seem to see where I am going wrong...............can anyone help? I can compile it but I just keep getting this one error I can't fix.....................
Program Name:     Transfer
import java.io.*;
import java.awt.*;
import java.awt.event.*;
public class Transfer extends Frame implements ActionListener
DataOutputStream output;
//Construct components
Panel dataFields = new Panel();
Panel firstRow = new Panel();
Panel secondRow = new Panel();
Panel thirdRow = new Panel();
Panel fourthRow = new Panel();
Panel buttonArea = new Panel();
Button submit = new Button("Submit");
Button exit = new Button("Exit");
Label firstNameLabel = new Label("Name:");
TextField firstName = new TextField(15);
Label studentIdLabel = new Label("Student ID:");
TextField studentId = new TextField(15);
Label transferCourseLabel = new Label("Transfer Course Number:");
TextField transferCourse = new TextField (15);
Label localCourseLabel = new Label("Local Course Number:");
TextField localCourses = new TextField (15);
public static void main(String args[])
Transfer window = new Transfer();
window.setTitle("Transfer Course Substitutions");
window.setSize(450, 250);
window.setVisible(true);
public Transfer()
//set backgound and layout managers
setBackground(Color.magenta);
setLayout(new BorderLayout());
dataFields.setLayout(new GridLayout(4,2));
FlowLayout rowSetup = new FlowLayout(FlowLayout.LEFT,4,2);
firstRow.setLayout(rowSetup);
secondRow.setLayout(rowSetup);
thirdRow.setLayout(rowSetup);
fourthRow.setLayout(rowSetup);
buttonArea.setLayout(new FlowLayout());
//Add fields to rows
firstRow.add(firstNameLabel);
secondRow.add(studentIdLabel);
thirdRow.add(transferCourseLabel);
fourthRow.add(localCourseLabel);
//Add rows to panel
dataFields.add(firstRow);
dataFields.add(secondRow);
dataFields.add(thirdRow);
dataFields.add(fourthRow);
//Add buttons to panel
buttonArea.add(submit);
buttonArea.add(exit);
//Add panels to frame
add(dataFields, BorderLayout.NORTH);
add(buttonArea, BorderLayout.SOUTH);
//Add functionality to buttons
submit.addActionListener(this);
exit.addActionListener(this);
// output states
try
output = new DataOuputStream(new FileOUtputStream("Transfer.dat"));
catch(IOException ex)
System.exit(1);
//construct window listener
addWindowListener(
new WindowAdapter()
public void windowClosing(WindowEvent e)
System.exit(0);
public void actionPerformed(ActionEvent e)
String arg = e.getActionCommand();
if (arg == "Submit")
try
output.writeUTF(code);
output.writeUTF(firstName.getText());
output.writeUTF(studentId.getText());
output.writeUTF(transferCourse.getText());
output.writeUTF(localCourse.getText());
catch(IOException ex)
System.exit(1);
clearFields();
else //code to execute if the user clicks Exit
try
output.close();
catch(IOException c)
System.exit(1);
System.exit(0);
public void clearFields()
firstName.setText("");
studentId.setText("");
transferCourse.setText("");
localCourse.setText("");
firstName.requestFocus();

Answer 1

The == method does work but it compares Object references and not the String contents. If the string you are comparing is actually the same object it will reply with 'true' also id both Strings are generated with quotes in the same methos and they contain the same string it will also work. This because the compiler will optimize your creating 2 identical Strings to 1 crete statement.
String a = "Hello";
String b = "Hello";
String c = new String("Hello");
String d = "He" + "llo";
String e = "He";
e +="llo";
a == b ==> true : because of optimization
a == c ==> false: because of different objects
a.equals(c) ==> true
a == d ==> true : because of optimization
a == e ==> false : because of different objects