Hi I have been having problems with this on both netbeans and eclipse even with a simple file that displays a jframe with a jlabel on it. My netbeans's project properties clearly sets testing2.hihi as my Main class and I have clean and build it which produces a .jar file in my dist folder. When I double click on it, it gives me the message" could not find the main class. Program will exit." However, if I choose to run it from the command prompt "java -jar hello2.jar" it will run as normal! Can anyone help me with this? Thanks alot!

  package testing2;

public class hihi extends javax.swing.JFrame {

/**
 * Creates new form hihi
 */
public hihi() {
    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.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jLabel1.setText("hihi");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(50, 50, 50)
            .addComponent(jLabel1)
            .addContainerGap(334, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(33, 33, 33)
            .addComponent(jLabel1)
            .addContainerGap(253, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /*
     * Set the Nimbus look and feel
     */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /*
     * If Nimbus (introduced in Java SE 6) is not available, stay with the
     * default look and feel. For details see
     * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(hihi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(hihi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(hihi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(hihi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /*
     * Create and display the form
     */
    java.awt.EventQueue.invokeLater(new Runnable() {

        public void run() {
            new hihi().setVisible(true);
        }
    });
}
// Variables declaration - do not modify
private javax.swing.JLabel jLabel1;
// End of variables declaration