Hello, I'm not talking good English, this text is created with the help of the translator :) Sorry fot my English. I need help with save/load vector in class "GUI" in Actiolistener on the Button "Vytvor" (create) and Button "Zobraz"(Show). When i click on "Zobraz" (show), in JTextArray have the vector value "null". Here ist my complete project: uploaded.to - where your files have to be uploaded to
I post here my code, I hope you understand me :)
Thank you very much.

Class GUI:
Java Code:
import java.util.Vector;
import java.awt.*;
import javax.swing.*;
import java.awt.GridBagConstraints;
import java.io.FileNotFoundException;
import java.io.IOException;

public class GUI extends JFrame {

	
    private Serializacia ser = new Serializacia();  //  @jve:decl-index=0:
    private Vector vekt=new Vector();  //  @jve:decl-index=0:
    

    
    
   // for (int i=0;i<vekt.size();i++)
   // { jTextArea.append(subor.elementAt(i).toString());
    
    
    
    
	private static final long serialVersionUID = 1L;
	private JPanel jContentPane = null;
	private JPanel vrch = null;
	private JLabel meno = null;
	private JLabel vek = null;
	private JLabel Priezvisko = null;
	private JLabel fakulta = null;
	private JButton vytvor = null;
	private JTextField Tmeno = null;
	private JTextField Tpriezvisko = null;
	private JTextField Tvek = null;
	private JTextField Tfakulta = null;
	private JTextArea jTextArea = null;
	private JButton zobraz = null;
	private JPanel dole = null;
	private JButton vymazat = null;
	private JButton plusrok = null;
	private JTextField Tid = null;
	private JPanel bok = null;
	/**
	 * This is the default constructor
	 */
	public GUI() {
		super();
		initialize();
	}

	/**
	 * This method initializes this
	 * 
	 * @return void
	 */
	private void initialize() {
		this.setSize(400, 246);
		this.setContentPane(getJContentPane());
		this.setTitle("JFrame");
	}

	/**
	 * This method initializes jContentPane
	 * 
	 * @return javax.swing.JPanel
	 */
	private JPanel getJContentPane() {
		if (jContentPane == null) {
			jContentPane = new JPanel();
			jContentPane.setLayout(new BorderLayout());
			jContentPane.add(getVrch(), BorderLayout.NORTH);
			jContentPane.add(getJTextArea(), BorderLayout.CENTER);
			jContentPane.add(getDole(), BorderLayout.SOUTH);
			jContentPane.add(getBok(), BorderLayout.EAST);
		}
		return jContentPane;
	}

	/**
	 * This method initializes vrch	
	 * 	
	 * @return javax.swing.JPanel	
	 */
	private JPanel getVrch() {
		if (vrch == null) {
			fakulta = new JLabel();
			fakulta.setText("Fakulta");
			fakulta.setDisplayedMnemonic(KeyEvent.VK_UNDEFINED);
			fakulta.setEnabled(true);
			Priezvisko = new JLabel();
			Priezvisko.setText("Priezvisko");
			vek = new JLabel();
			vek.setText("Vek");
			meno = new JLabel();
			meno.setText("Meno");
			GridLayout gridLayout1 = new GridLayout();
			gridLayout1.setRows(2);
			gridLayout1.setHgap(2);
			gridLayout1.setVgap(2);
			gridLayout1.setColumns(5);
			vrch = new JPanel();
			vrch.setLayout(gridLayout1);
			vrch.setPreferredSize(new Dimension(0, 50));
			vrch.setMinimumSize(new Dimension(0, 50));
			vrch.add(meno, null);
			vrch.add(Priezvisko, null);
			vrch.add(fakulta, null);
			vrch.add(vek, null);
			vrch.add(getVytvor(), null);
			vrch.add(getTmeno(), null);
			vrch.add(getTpriezvisko(), null);
			vrch.add(getTfakulta(), null);
			vrch.add(getTvek(), null);
		}
		return vrch;
	}

	/**
	 * This method initializes vytvor	
	 * 	
	 * @return javax.swing.JButton	
	 */
	private JButton getVytvor() {
		if (vytvor == null) {
			vytvor = new JButton();
			vytvor.setMnemonic(KeyEvent.VK_UNDEFINED);
			vytvor.setText("Vytvor");
			vytvor.addActionListener(new java.awt.event.ActionListener() {
				public void actionPerformed(java.awt.event.ActionEvent e) {
					System.out.println("actionPerformed()"); // TODO Auto-generated Event stub actionPerformed()
					
					
					ser.set(Tmeno.getText(), Tpriezvisko.getText(), Tfakulta.getText(),Integer.parseInt(Tvek.getText()));
		 	        Tmeno.setText("");
		 	        Tmeno.setText("");
		 	        Tpriezvisko.setText("");
		 	        Tfakulta.setText("");
		 	        Tvek.setText("");
		 	        
		 	       try {
						ser.save("./pamat.ser");
					} catch (FileNotFoundException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					} catch (IOException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					}
					
				}
			});
		}
		return vytvor;
	}

	/**
	 * This method initializes Tmeno	
	 * 	
	 * @return javax.swing.JTextField	
	 */
	private JTextField getTmeno() {
		if (Tmeno == null) {
			Tmeno = new JTextField();
		}
		return Tmeno;
	}

	/**
	 * This method initializes Tpriezvisko	
	 * 	
	 * @return javax.swing.JTextField	
	 */
	private JTextField getTpriezvisko() {
		if (Tpriezvisko == null) {
			Tpriezvisko = new JTextField();
		}
		return Tpriezvisko;
	}

	/**
	 * This method initializes Tvek	
	 * 	
	 * @return javax.swing.JTextField	
	 */
	private JTextField getTvek() {
		if (Tvek == null) {
			Tvek = new JTextField();
		}
		return Tvek;
	}

	/**
	 * This method initializes Tfakulta	
	 * 	
	 * @return javax.swing.JTextField	
	 */
	private JTextField getTfakulta() {
		if (Tfakulta == null) {
			Tfakulta = new JTextField();
		}
		return Tfakulta;
	}

	/**
	 * This method initializes jTextArea	
	 * 	
	 * @return javax.swing.JTextArea	
	 */
	private JTextArea getJTextArea() {
		if (jTextArea == null) {
			jTextArea = new JTextArea();
		}
		return jTextArea;
	}

	/**
	 * This method initializes zobraz	
	 * 	
	 * @return javax.swing.JButton	
	 */
	
	
	
	
	private JButton getZobraz() {
		if (zobraz == null) {
			zobraz = new JButton();
			zobraz.setText("Zobraz");
			zobraz.addActionListener(new java.awt.event.ActionListener() {
				public void actionPerformed(java.awt.event.ActionEvent e) {
					System.out.println("actionPerformed()"); // TODO Auto-generated Event stub actionPerformed()
				    
					/*	vekt = ser.get();
			        jTextArea.setText("");
			        for (int i=0;i<vekt.size();i++)
			        {
			            jTextArea.append(vekt.elementAt(i).toString());
			        } */
					
                   try {
					vekt = ser.load("./pamat.ser");
				} catch (FileNotFoundException e2) {
					// TODO Auto-generated catch block
					e2.printStackTrace();
				} catch (IOException e2) {
					// TODO Auto-generated catch block
					e2.printStackTrace();
				} catch (ClassNotFoundException e2) {
					// TODO Auto-generated catch block
					e2.printStackTrace();
				}
                   jTextArea.setText("");
			        for (int i=0;i<vekt.size();i++)
			        {
			        	jTextArea.append(vekt.elementAt(i).toString());
			        }
			        
					
					
			        
				
				}
			});
		}
		return zobraz;
	}

	/**
	 * This method initializes dole	
	 * 	
	 * @return javax.swing.JPanel	
	 */
	private JPanel getDole() {
		if (dole == null) {
			GridLayout gridLayout3 = new GridLayout();
			gridLayout3.setRows(2);
			GridLayout gridLayout2 = new GridLayout();
			gridLayout2.setRows(2);
			GridLayout gridLayout11 = new GridLayout();
			gridLayout11.setRows(2);
			GridLayout gridLayout = new GridLayout();
			gridLayout.setRows(2);
			gridLayout.setColumns(2);
			dole = new JPanel();
			dole.setLayout(gridLayout3);
			dole.setMinimumSize(new Dimension(0, 50));
			dole.setPreferredSize(new Dimension(0, 50));
			dole.add(getVymazat(), null);
			dole.add(getPlusrok(), null);
			dole.add(getTid(), null);
		}
		return dole;
	}

	/**
	 * This method initializes vymazat	
	 * 	
	 * @return javax.swing.JButton	
	 */
	private JButton getVymazat() {
		if (vymazat == null) {
			vymazat = new JButton();
			vymazat.setPreferredSize(new Dimension(34, 20));
			vymazat.setText("Vymazat");
		}
		return vymazat;
	}

	/**
	 * This method initializes plusrok	
	 * 	
	 * @return javax.swing.JButton	
	 */
	private JButton getPlusrok() {
		if (plusrok == null) {
			plusrok = new JButton();
			plusrok.setText("Dalsi akademicky rok");
		}
		return plusrok;
	}

	/**
	 * This method initializes Tid	
	 * 	
	 * @return javax.swing.JTextField	
	 */
	private JTextField getTid() {
		if (Tid == null) {
			Tid = new JTextField();
		}
		return Tid;
	}

	/**
	 * This method initializes bok	
	 * 	
	 * @return javax.swing.JPanel	
	 */
	private JPanel getBok() {
		if (bok == null) {
			GridLayout gridLayout4 = new GridLayout();
			gridLayout4.setColumns(1);
			gridLayout4.setRows(1);
			bok = new JPanel();
			bok.setLayout(gridLayout4);
			bok.setMinimumSize(new Dimension(100, 0));
			bok.setPreferredSize(new Dimension(100, 0));
			bok.add(getZobraz(), null);
		}
		return bok;
	}
}
Class for save/load
Java Code:
import java.io.*;


import java.util.Vector;

public class Serializacia {
	private  Vector vektor = new Vector();
	
	
	public Vector load(String file) throws FileNotFoundException, IOException, ClassNotFoundException{
		File subor = new File(file);
		if (subor.exists()) {
			ObjectInputStream ois = new ObjectInputStream(new FileInputStream(subor));
			vektor = (Vector)ois.readObject();
		}
		return vektor;
	}
	
	public void save(String file) throws FileNotFoundException, IOException{
                 
		File subor = new File(file);
		ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(subor));
		oos.writeObject(vektor);
		oos.close();
	}
	
	public void set(String meno, String priezvisko, String fakulta, int vek){ 
	Student xxx = new Student(meno,priezvisko,fakulta,vek);
	vektor.add(xxx);
	
	//pocet=pocet+1;
	
	}
	
	public void delete(int poz){
		int vel = vektor.size()-1;
		for (int i=poz;i<vel;i++){
			vektor.setElementAt(vektor.elementAt(i+1),i);
		}
		vektor.setElementAt(null,vel);
	}
	
	public Vector get(){
	return vektor;
        }
}