não consigo posicionar os itens no JPanel alguém ajuda?

Assuntos Gerais
#1

[code]package visao;

import java.awt.Color;
import java.awt.Container;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

/**
*

  • @author Paulo
    */
    public class JanelaTipo extends JFrame implements ActionListener{
    private final Container c;
    private final JLabel lblTeste;
    private final JTextField txTest;
    private final JComboBox jcSelect;
    private final JButton btCadastro,btVoltar;
    private final JPanel jpCliente,jpFuncionario,jpUsuario;
    private LayoutManager FlowLayout;

    public JanelaTipo() {

     super("Gerenciamento de Membros");
 //TEXTFIELD
 this.txTest = new JTextField();
 this.txTest.setBounds(10, 10, 100, 30);
 //JLABEL
 this.lblTeste = new JLabel("TESTANDO");
 this.lblTeste.setBounds(0, 0, 0, 0);
 
 //PANELCLIENTE
 this.jpCliente = new JPanel();
 this.jpCliente.setLayout(null);
 this.jpCliente.setBounds(100,25,405,320);
 this.jpCliente.setBackground(Color.red);        
 this.jpCliente.setVisible(false);
 
 //PANELUSER
 this.jpUsuario = new JPanel();
 this.jpUsuario.setBounds(100,25,405,320);
 this.jpUsuario.setBackground(Color.cyan);
 this.jpUsuario.setVisible(false);
 
 //PANELFUNC
 this.jpFuncionario = new JPanel();
 this.jpFuncionario.setBounds(100,25,405,320);
 this.jpFuncionario.setBackground(Color.yellow);
 this.jpFuncionario.setVisible(false);
 
 //JBUTTON
 this.btCadastro = new JButton("Cadastrar");
 this.btCadastro.setBounds(0,0,495,25);
 this.btCadastro.addActionListener(this);
 this.btCadastro.setActionCommand("btCadastro");
 
 this.btVoltar = new JButton("Voltar");
 this.btVoltar.setBounds(0, 345,495, 25);
 this.btVoltar.addActionListener(this);
 this.btVoltar.setActionCommand("btVoltar");
 
 //JCombobox
 this.jcSelect = new JComboBox();
 this.jcSelect.setBounds(0, 26, 100, 200);
 
 
 //itensJCombobox
 jcSelect.addActionListener(this);
 jcSelect.addItem("Selecionar");
 jcSelect.addItem("Usuario");
 jcSelect.addItem("Cliente");
 jcSelect.addItem("Funcionario");
 
 super.getContentPane().add(this.jcSelect);
 super.getContentPane().add(this.btCadastro);
 super.getContentPane().add(this.btVoltar);
 super.getContentPane().add(this.jpCliente);
 super.getContentPane().add(this.jpFuncionario);
 super.getContentPane().add(this.jpUsuario);
 
 
 //JANELA
 this.c = super.getContentPane();
 super.setLayout(null);
 super.setSize(500, 400);
 super.setLocationRelativeTo(null);    
 super.setResizable(false);
 super.setDefaultCloseOperation(super.EXIT_ON_CLOSE);
 super.setVisible(true);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
    if(e.getActionCommand().equals(this.btVoltar.getActionCommand())){
    JanelaMembros x = new JanelaMembros();
    dispose();
    }

     JComboBox itemselecionado =(JComboBox)e.getSource();  
 String selecionado = (String)itemselecionado.getSelectedItem().toString();  
 System.out.println(selecionado);
 if (selecionado.equalsIgnoreCase("Usuario")){  
     this.jpUsuario.setVisible(true);
     this.jpCliente.setVisible(false);
     this.jpFuncionario.setVisible(false);

    }
    if (selecionado.equalsIgnoreCase(“Cliente”)){
    this.jpUsuario.setVisible(false);
    this.jpCliente.setVisible(true);
    this.jpFuncionario.setVisible(false);
    }
    if(selecionado.equalsIgnoreCase(“Funcionario”)){
    this.jpUsuario.setVisible(false);
    this.jpCliente.setVisible(false);
    this.jpFuncionario.setVisible(true);
    }
    if(selecionado.equalsIgnoreCase(“Selecionar”)){
    this.jpUsuario.setVisible(false);
    this.jpCliente.setVisible(false);
    this.jpFuncionario.setVisible(false);
    }

     }

}[/code]

#2

http://docs.oracle.com/javase/tutorial/uiswing/layout/index.html

#3