I finished my little app. so now i would like to see the result by command prompt. (in eclipse works well).
first step i decided (to be sure) to compile by command prompt my program:
javac appNegozio.java
i compiled without error in fact i have my files .class (all the program have just 1 class but i have some inner class and so i have more than 1 file .class)
now if i try to run my program:
java appNegozio
i have this problem on the prompt:
Exception in thread "main" java.lang.NoClassDefFoundError: appNegozio (wrong nam
    e: prgStore/appNegozio)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$100(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
but i don't understand why... and what i have to do...
this is my code: >
package prgStore;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.SpringLayout;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class appNegozio extends JFrame {
private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    appNegozio frame = new appNegozio();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    /**
     * Create the frame.
     */
    public appNegozio() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        SpringLayout sl_contentPane = new SpringLayout();
        contentPane.setLayout(sl_contentPane);
        textField = new JTextField();
        sl_contentPane.putConstraint(SpringLayout.NORTH, textField, 10, SpringLayout.NORTH, contentPane);
        sl_contentPane.putConstraint(SpringLayout.WEST, textField, 62, SpringLayout.WEST, contentPane);
        contentPane.add(textField);
        textField.setColumns(10);
        textField_1 = new JTextField();
        sl_contentPane.putConstraint(SpringLayout.NORTH, textField_1, 16, SpringLayout.SOUTH, textField);
        sl_contentPane.putConstraint(SpringLayout.WEST, textField_1, 0, SpringLayout.WEST, textField);
        contentPane.add(textField_1);
        textField_1.setColumns(10);
        JLabel lblNome = new JLabel("Nome");
        sl_contentPane.putConstraint(SpringLayout.NORTH, lblNome, 10, SpringLayout.NORTH, contentPane);
        sl_contentPane.putConstraint(SpringLayout.EAST, lblNome, -7, SpringLayout.WEST, textField);
        contentPane.add(lblNome);
        JLabel lblCognome = new JLabel("Cognome");
        sl_contentPane.putConstraint(SpringLayout.NORTH, lblCognome, 0, SpringLayout.NORTH, textField_1);
        sl_contentPane.putConstraint(SpringLayout.EAST, lblCognome, -6, SpringLayout.WEST, textField_1);
        contentPane.add(lblCognome);
        JButton btnSubmit = new JButton("Submit");
        btnSubmit.addActionListener(new ActionListener() {
            int a, b;
            public void actionPerformed(ActionEvent e) {
                System.out.println();
            }
        });
        sl_contentPane.putConstraint(SpringLayout.NORTH, btnSubmit, 24, SpringLayout.SOUTH, textField_1);
        sl_contentPane.putConstraint(SpringLayout.WEST, btnSubmit, 10, SpringLayout.WEST, contentPane);
        contentPane.add(btnSubmit);
    }
}
    package prgStore;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.SpringLayout;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class appNegozio extends JFrame {
    private JPanel contentPane;
    private JTextField textField;
    private JTextField textField_1;
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    appNegozio frame = new appNegozio();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    /**
     * Create the frame.
     */
    public appNegozio() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        SpringLayout sl_contentPane = new SpringLayout();
        contentPane.setLayout(sl_contentPane);
        textField = new JTextField();
        sl_contentPane.putConstraint(SpringLayout.NORTH, textField, 10, SpringLayout.NORTH, contentPane);
        sl_contentPane.putConstraint(SpringLayout.WEST, textField, 62, SpringLayout.WEST, contentPane);
        contentPane.add(textField);
        textField.setColumns(10);
        textField_1 = new JTextField();
        sl_contentPane.putConstraint(SpringLayout.NORTH, textField_1, 16, SpringLayout.SOUTH, textField);
        sl_contentPane.putConstraint(SpringLayout.WEST, textField_1, 0, SpringLayout.WEST, textField);
        contentPane.add(textField_1);
        textField_1.setColumns(10);
        JLabel lblNome = new JLabel("Nome");
        sl_contentPane.putConstraint(SpringLayout.NORTH, lblNome, 10, SpringLayout.NORTH, contentPane);
        sl_contentPane.putConstraint(SpringLayout.EAST, lblNome, -7, SpringLayout.WEST, textField);
        contentPane.add(lblNome);
        JLabel lblCognome = new JLabel("Cognome");
        sl_contentPane.putConstraint(SpringLayout.NORTH, lblCognome, 0, SpringLayout.NORTH, textField_1);
        sl_contentPane.putConstraint(SpringLayout.EAST, lblCognome, -6, SpringLayout.WEST, textField_1);
        contentPane.add(lblCognome);
        JButton btnSubmit = new JButton("Submit");
        btnSubmit.addActionListener(new ActionListener() {
            int a, b;
            public void actionPerformed(ActionEvent e) {
                System.out.println();
            }
        });
        sl_contentPane.putConstraint(SpringLayout.NORTH, btnSubmit, 24, SpringLayout.SOUTH, textField_1);
        sl_contentPane.putConstraint(SpringLayout.WEST, btnSubmit, 10, SpringLayout.WEST, contentPane);
        contentPane.add(btnSubmit);
    }
}
 thank you

