MenComboBox em JTable Serialização erro

Boa tarde!

Gostaria de perguntar se algum sabe o por que do erro abaixo:
Tenho um JTable com os campos
JComboBox | MenComboBox | MenComboBox

O JComboBox é atualizado por banco de dados, já os MenComboBox eu salvo os itens em arquivo no disco com serialização.
O erro acontece da seguinte forma, se eu clicar no JComboBox e escolher qualquer opção, mesmo que eu não clique nos MenCombobox, quando mando salvar os MenComboBox da o erro de serialização abaixo:
java.io.NotSerializableException: expedicao.persistencia.CadastroSQL

Se eu abrir a janela não clicar no JComboBox, manipular os MenConboBox mando salvar e não gera erro algum, posso fazer isso diversas vezes os salvar diversos itens no MenComboBox que não gera erro algum.
a class que esta dando erro CadastroSQL é responsavel por ler os dados do banco de dados e entregar uma String[] para o JComboBox, e esta funcionando.

Não entendo porque Componentes sem ligação alguma(exceto a JTable que liga todos) estão gerando esse erro, posso colar o codigo mas esta grande ><

Vou colar apenas os trexos:

        JComboBox produtoBox = new JComboBox();
        sql = new CadastroSQL();
        update();
        TableColumn produto = getColumnModel().getColumn(1);
        produto.setCellEditor(new DefaultCellEditor(produtoBox));
    private void update() {
        produtoBox.removeAllItems();
        try {
            itens = sql.getDados();
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
        for(int i  = 0; i < itens.length; i++){
            produtoBox.addItem(itens[i]);
        }
    }
    public void comboPlaca(String arqNome, int col){
        placa = new MenComboBox();
        new MenComboAgent(placa);
        placa.loader(arqNome);
        TableColumn p = getColumnModel().getColumn(col);
        p.setCellEditor(new DefaultCellEditor(placa));
    }
    public void saveComboBoxs(){
        placa.add((String)placa.getSelectedItem());
        placa.save("2.dat");
   }
Serialization error 2: java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1333)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at javax.swing.JComponent.readObject(JComponent.java:5408)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at javax.swing.event.EventListenerList.readObject(EventListenerList.java:255)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at expedicao.myclass.MenComboBox.loader(MenComboBox.java:43)
        at expedicao.myclass.TablePedidos.comboPlaca(TablePedidos.java:90)
        at expedicao.myclass.TablePedidos.showTableDados(TablePedidos.java:64)
        at expedicao.frmPedido.<init>(frmPedido.java:40)
        at expedicao.ExpedicaoView.jMenuItem2ActionPerformed(ExpedicaoView.java:388)
        at expedicao.ExpedicaoView.access$1000(ExpedicaoView.java:33)
        at expedicao.ExpedicaoView$6.actionPerformed(ExpedicaoView.java:313)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
        at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
        at java.awt.Component.processMouseEvent(Component.java:6263)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6028)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Caused by: java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at javax.swing.ArrayTable.writeArrayTable(ArrayTable.java:70)
        at javax.swing.JComponent.writeObject(JComponent.java:5439)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at javax.swing.event.EventListenerList.writeObject(EventListenerList.java:240)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at expedicao.myclass.MenComboBox.save(MenComboBox.java:59)
        at expedicao.myclass.TablePedidos.saveComboBoxs(TablePedidos.java:177)
        at expedicao.frmPedido.jButton1ActionPerformed(frmPedido.java:273)
        at expedicao.frmPedido.access$400(frmPedido.java:34)
        at expedicao.frmPedido$4.actionPerformed(frmPedido.java:198)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        ... 20 more
Serialization error 2: java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1333)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at javax.swing.JComponent.readObject(JComponent.java:5408)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at javax.swing.event.EventListenerList.readObject(EventListenerList.java:255)
        at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at expedicao.myclass.MenComboBox.loader(MenComboBox.java:43)
        at expedicao.myclass.TablePedidos.comboCliente(TablePedidos.java:97)
        at expedicao.myclass.TablePedidos.showTableDados(TablePedidos.java:65)
        at expedicao.frmPedido.<init>(frmPedido.java:40)
        at expedicao.ExpedicaoView.jMenuItem2ActionPerformed(ExpedicaoView.java:388)
        at expedicao.ExpedicaoView.access$1000(ExpedicaoView.java:33)
        at expedicao.ExpedicaoView$6.actionPerformed(ExpedicaoView.java:313)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
        at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
        at java.awt.Component.processMouseEvent(Component.java:6263)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6028)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Caused by: java.io.NotSerializableException: expedicao.persistencia.CadastroSQL
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at javax.swing.ArrayTable.writeArrayTable(ArrayTable.java:70)
        at javax.swing.JComponent.writeObject(JComponent.java:5439)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at javax.swing.event.EventListenerList.writeObject(EventListenerList.java:240)
        at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at expedicao.myclass.MenComboBox.save(MenComboBox.java:59)
        at expedicao.myclass.TablePedidos.saveComboBoxs(TablePedidos.java:179)
        at expedicao.frmPedido.jButton1ActionPerformed(frmPedido.java:273)
        at expedicao.frmPedido.access$400(frmPedido.java:34)
        at expedicao.frmPedido$4.actionPerformed(frmPedido.java:198)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        ... 20 more

Esta dificil ajudar, sei, pelo que conheço de Serialização é como se estivesse serializando um componente e tentando ler e aplicar em outro ><

CadastroSQL e outras classes envolvidas no processo implementam a interface Serializable?

Bom dia!

Não, antes do erro não implementava porque não interage no processo do MenComboBox, mas apos o erro tentei implements Serializable,… mas não resolveu. a Class cadastroSQL é totalmente serializable se fosse o caso.