保存按钮抛出错误：线程“AWT-EventQueue-0”中的异常java.lang.NullPointerException

Question

我有一个带有以下代码的表单的“保存按钮”。单击时，文本框中的数据应保存到数据库中。 该按钮还包含一个try..catch块来处理资源清理以防止锁定。

 private void saveBtnActionPerformed(java.awt.event.ActionEvent evt) {                                        

    String user = usernameText.getText();
    String pass = passwordField.getText();
    String pass2 = confirmPasswordField.getText();
    String job = jobBox.getSelectedItem().toString();

   try{
       if (pass2.equals(pass)) {

            rs.moveToInsertRow();

            rs.updateString("username", user);
            rs.updateString("password", pass);
            rs.updateString("jobtitle", job);

            rs.insertRow();

            JOptionPane.showMessageDialog(this, "New Record Has Been Added!");

       }

       else {
            JOptionPane.showMessageDialog(this, "Your passwords do not match");


            this.dispose();

            newEmployeeFrame a = new newEmployeeFrame();
            a.setVisible(true);

        }

   }
   catch(SQLException err){

   }
   finally{
       try{
        rs.close();
        stmt.close();
        this.dispose();

        newEmployeeFrame a = new newEmployeeFrame();
        a.setVisible(true);
        }

        catch(Exception e){
            //try-catch block to encapsulate finally block for resource closing
            //to prevent lock obtain error
        }

当我点击它时，我收到以下错误消息：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at newEmployeeFrame.saveBtnActionPerformed(newEmployeeFrame.java:195)
at newEmployeeFrame.access$100(newEmployeeFrame.java:19)
at newEmployeeFrame$2.actionPerformed(newEmployeeFrame.java:76)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6516)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3320)
at java.awt.Component.processEvent(Component.java:6281)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4872)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4698)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4698)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:708)
at java.awt.EventQueue$4.run(EventQueue.java:706)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)
BUILD SUCCESSFUL (total time: 13 seconds)

请帮助..谢谢！