How can i call a JFrame from a class?

Question

I have an project which have a Jframe under a default package.I cant call the jframe from a another main class .

public class NewJFrame extends javax.swing.JFrame {

    /**
     * Creates new form NewJFrame
     */
    public NewJFrame() {
        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("         Hello");

        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(113, 113, 113)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 111, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(176, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(86, 86, 86)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 49, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(165, 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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.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 NewJFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JLabel jLabel1;
    // End of variables declaration
}

another class is : A.java

package a;



/**
 *
 * @author Anupom
 */
public class A {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
         java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new NewJFrame().setVisible(true);
            }
        });
    }
}

Answer 1

Do you get any errors ? if so - State the here so we can see

Also on the 'other' class just do this

public static void main(String[] args) {
    NewJFrame frame = new NewJFrame();
    frame.setVisible(true);
}

Also on your JFrame class instead of

... extends javax.swing.JFrame

just do 

extends JFrame

And then you will be able to add import at the top of this class

import javax.swing*;

And as a result all method that are used by swing in your code wont have to have this javax.swing (pre-annotation is that correct term? )

you don't need all that auto generated crap ;)

EDIT: Slightly cleaner solution for you :)

import javax.swing*;

public class NewJFrame extends JFrame {
    private JLabel jLabel1;

    public NewJFrame() {
        initComponents();
    }

    private void initComponents() {
        jLabel1 = new JLabel();

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("         Hello");

        GroupLayout layout = new GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                .addGap(113, 113, 113)
                .addComponent(jLabel1, GroupLayout.PREFERRED_SIZE, 111, GroupLayout.PREFERRED_SIZE)
                .addContainerGap(176, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                .addGap(86, 86, 86)
                .addComponent(jLabel1, GroupLayout.PREFERRED_SIZE, 49, GroupLayout.PREFERRED_SIZE)
                .addContainerGap(165, Short.MAX_VALUE))
        );
        pack();
    }

    public static void main(String args[]) {        
        try {
            for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } 
        new NewJFrame().setVisible(true);
    }    
}