Newbie help with JAR files

Question

Okay,
I built a simple Hello World project with Swing and it worked. Now I've build my own program from scratch and get a "Cannot find the main class" error from the JRE. Below are the contents of the manafest file craeted by Sun Java Studio 8.
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.2
Created-By: 1.5.0_06-b05 (Sun Microsystems Inc.)
Main-Class: localPkg.mainForm
X-COMMENT: Main-Class will be added automatically by build
Also here is the source code for localPkg.mainForm
* mainForm.java
* Created on January 17, 2006, 9:32 AM
* @author rowen
package localPkg;
import java.beans.*;
public class mainForm extends javax.swing.JFrame {
/** Creates new form mainForm */
public mainForm() {
initComponents();
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
// <editor-fold defaultstate="collapsed" desc=" Generated Code ">
private void initComponents() {
java.awt.GridBagConstraints gridBagConstraints;
ctoF1 = new MyBeans.CtoF();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
numericField1 = new magicbeans.NumericField();
numericField2 = new magicbeans.NumericField();
ctoF1.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
ctoF1PropertyChange(evt);
ctoF1PropertyChange1(evt);
getContentPane().setLayout(new java.awt.GridBagLayout());
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Farenheight");
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 0;
gridBagConstraints.gridwidth = 2;
gridBagConstraints.ipadx = 2;
gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
gridBagConstraints.insets = new java.awt.Insets(20, 110, 0, 0);
getContentPane().add(jLabel1, gridBagConstraints);
jLabel2.setText("Celsius");
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 2;
gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
gridBagConstraints.insets = new java.awt.Insets(11, 110, 0, 0);
getContentPane().add(jLabel2, gridBagConstraints);
numericField1.setText("farenheightField");
numericField1.setName("farenheightField");
numericField1.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
numericField1PropertyChange(evt);
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 1;
gridBagConstraints.gridwidth = 4;
gridBagConstraints.ipadx = 119;
gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
gridBagConstraints.insets = new java.awt.Insets(6, 110, 0, 160);
getContentPane().add(numericField1, gridBagConstraints);
numericField2.setText("celsiusField");
numericField2.setName("celsiusField");
numericField2.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
numericField2PropertyChange(evt);
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 3;
gridBagConstraints.gridwidth = 3;
gridBagConstraints.ipadx = 99;
gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
gridBagConstraints.insets = new java.awt.Insets(6, 110, 191, 0);
getContentPane().add(numericField2, gridBagConstraints);
pack();
// </editor-fold>
private void numericField2PropertyChange(java.beans.PropertyChangeEvent evt) {                                            
ctoF1.setC(numericField2.getValue());
private void numericField1PropertyChange(java.beans.PropertyChangeEvent evt) {                                            
ctoF1.setF(numericField1.getValue());
private void ctoF1PropertyChange1(java.beans.PropertyChangeEvent evt) {                                     
numericField2.setValue(ctoF1.getC());
private void ctoF1PropertyChange(java.beans.PropertyChangeEvent evt) {                                    
numericField1.setValue(ctoF1.getF());
* @param args the command line arguments
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new mainForm().setVisible(true);
// Variables declaration - do not modify
private MyBeans.CtoF ctoF1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private magicbeans.NumericField numericField1;
private magicbeans.NumericField numericField2;
// End of variables declaration
Using Sun Java Studio Enterprise 8 (patch 1), on Windows XP (most recent patches)
Thanks in advance,
Roy

Answer 1

R_Owen ,
One possible way of how to do it in JSE8 is:
1. Put all necessary lib jars to some place under src folder.
2. Add those jars into Compile-time libraries list (Project properties -> Libraries) for correct compilation
3. Switch to 'Files' JSE8 tab, open manifest.mf file (it's in projects root) and add your lib jars to it.
Syntax is:
Class-Path: relative URLs
That's it.
And Class-Path attribute description from JAR File Specification:
http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html#Main%20Attributes:
�Class-Path:
The value of this attribute specifies the relative URLs of the extensions or
libraries that this application or extension needs.
URLs are separated by one or more spaces.
The application or extension class loader uses the value
of this attribute to construct its internal search path. �
Copy/paste from:
http://swforum.sun.com/jive/thread.jspa?forumID=122&threadID=60169