title: Could not find or load main Class on JAR executing
body: <p>I finished my project (in <code>NetBeans</code>) and i export <code>Jar</code> file (i set my main class in project properties correctly before exporting <code>Jar</code>):</p>
  
  <p><img src="https://i.stack.imgur.com/OhTXC.png" alt="enter image description here"></p>
  
  <p>Now, This is my <code>JAR</code>:</p>
  
  <p><img src="https://i.stack.imgur.com/3msb4.png" alt="enter image description here"></p>
  
  <p>This Error shown when i run the <code>Jar</code> (in command line page):</p>
  
  <p><code>Could not find or load main Class on JAR executing</code></p>
  
  <p>This is my <code>MANIFEST.MF</code> information:</p>
  
  <pre><code>Manifest-Version: 1.0
  Ant-Version: Apache Ant 1.9.1
  Created-By: 1.7.0_11-b21 (Oracle Corporation)
  Class-Path: lib/mysql-connector-java-5.1.18-bin.jar
  X-COMMENT: Main-Class will be added automatically by build
  Main-Class: Project.LoginFrame
  </code></pre>
  
  <p>All of my classes are here:</p>
  
  <p><img src="https://i.stack.imgur.com/oqlNL.png" alt="enter image description here"></p>
  
  <p>I try in command line too:</p>
  
  <p><img src="https://i.stack.imgur.com/IHrmz.png" alt="enter image description here"></p>
  
  <p>My project executed at this time, But all pictures (that are in a folder) not displayed, and also an <code>sql Exception</code> happens:</p>
  
  <p><img src="https://i.stack.imgur.com/U32DW.png" alt="enter image description here"></p>
  
  <p><strong>Update:</strong></p>
  
  <pre><code>package Project;
  
  import javax.imageio.ImageIO;
  import javax.swing.*;
  import javax.swing.plaf.nimbus.NimbusLookAndFeel;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.awt.image.BufferedImage;
  import java.io.File;
  import java.io.IOException;
  import java.sql.*;
  
  public class LoginFrame extends javax.swing.JFrame implements ActionListener {
  
  String dbUrl = "jdbc:mysql://localhost/Library";
  private char[] Password;
  private JButton ClearBtn,ExitBtn,LoginBtn;
  private JLabel ErrorLbl;
  private JComboBox comboBox;
  private JLabel lbl1;
  private JLabel lbl2;
  private JLabel lbl3;
  private String[] enterUserInf = new String[4];
  private JPasswordField passwordField;
  private JTextField usernameTF;
  
  public LoginFrame() {
      initComponents();
      this.getRootPane().setDefaultButton(LoginBtn);
      comboBox.addActionListener(this);
      setVisible(true);
  }
  
  public static void main(String args[]) throws IOException {
      new LoginFrame();
  }
  
  private void initComponents() {
      //...
  }
  
  private void LoginButtonActionPerformed(java.awt.event.ActionEvent evt) {
  
      try {
          if (comboBox.getSelectedIndex() == 0) {
              ErrorLbl.setText("Select A Model...");
              ErrorLbl.setVisible(true);
              return;
          }
  
          Password = passwordField.getPassword();
  
          if (!passwordControl()) {
              return;
          }
  
          if (comboBox.getSelectedIndex() == 1) {
              if (userEnterCondition(Password)) {
                  this.setVisible(false);
                  new BookPage_User(enterUserInf, enterUserInf[0]);
              } else {
                  ErrorLbl.setText("Incorrect Password!");
              }
          }
  
          if (comboBox.getSelectedIndex() == 2) {
              if (adminEnterCondition(Password)) {
                  this.setVisible(false);
                  new MainFrame().setVisible(true);
              } else {
                  ErrorLbl.setText("Incorrect Password!");
              }
          }
      } catch (Exception e) {
          e.printStackTrace();
          ErrorLbl.setText("Enter Correct Input");
      }
  
  }
  
  private void ExitButtonActionPerformed(java.awt.event.ActionEvent evt) {
      System.exit(0);
  }
  
  private void ClearButtonActionPerformed(java.awt.event.ActionEvent evt) {
      passwordField.setText("");
  }
  
  public boolean passwordControl() {
      Password = passwordField.getPassword();
      if (String.valueOf(Password).trim().isEmpty()) {
          ErrorLbl.setText("Empty Password!");
          ErrorLbl.setVisible(true);
          return false;
      }
      return true;
  }
  
  public boolean adminEnterCondition(char[] pass) {
      Connection con;
      PreparedStatement preparedStatement;
      ResultSet resultSet;
      String query = "Select * From adminLogin";
      String password = null;
      try {
          con = DriverManager.getConnection(...);
          preparedStatement = con.prepareStatement(query);
          resultSet = preparedStatement.executeQuery();
          while (resultSet.next()) {
              password = resultSet.getString("ID");  // Get column value by name column name
              if (password.equalsIgnoreCase(String.valueOf(pass))) {
                  return true;
              }
          }
  
      } catch (SQLException sqle) {
          sqle.printStackTrace();
          return false;
      }
      return false;
  }
  
  public boolean userEnterCondition(char[] pass) {
      Connection con;
      PreparedStatement preparedStatement;
      ResultSet resultSet;
      String query = "Select * from users";
      String password = null;
      try {
          Class.forName("com.mysql.jdbc.Driver");
          con = DriverManager.getConnection(...);
          preparedStatement = con.prepareStatement(query);
          resultSet = preparedStatement.executeQuery();
          while (resultSet.next()) {
              password = resultSet.getString("User_ID");
          }
  
      } catch (SQLException sqle) {
          return false;
      } catch (ClassNotFoundException cnfe) {
      }
      return false;
  }
  
  @Override
  public void actionPerformed(ActionEvent e) {
      if (e.getSource() == comboBox) {
          if (comboBox.getSelectedIndex() == 1) {
              usernameTF.setText("User");
              usernameTF.setEditable(false);
              passwordField.requestFocusInWindow();
              ErrorLbl.setVisible(false);
          } else if (comboBox.getSelectedIndex() == 2) {
              passwordField.requestFocusInWindow();
          }
      }
  }
  }
  </code></pre>