Erro inserir no banco MySQL

Assuntos Gerais
#1

Esse é o código para conectar no banco;

[code]package utiliarios;

import java.sql.*;
import javax.swing.JOptionPane;

public class Conector {
final private String driver = “com.mysql.jdbc.Driver”;
final private String dbUrl=“jdbc:mysql://localhost:3306/test”;
final private String user=“root”;
final private String pwd=“123456”;
private Connection conexao;
public Statement statement;
public ResultSet resultset;

  public boolean conecta()
  {      
      boolean resul = true;
      try
      {
          Class.forName(driver);
          conexao = DriverManager.getConnection(dbUrl, user, pwd);
          JOptionPane.showMessageDialog(null,"Conectou");
      }catch(ClassNotFoundException Driver)
      {
          JOptionPane.showMessageDialog(null, "Driver não encontrado: "+Driver); 
          resul = false;
      }catch(SQLException Fonte){
          JOptionPane.showMessageDialog(null, "Erro na Conexão com o Banco: "+Fonte);
          resul = false;
      }
      return resul;
  }
  
  public void desconectar(){
      boolean resul = true;
      
      try{
          conexao.close();
          JOptionPane.showMessageDialog(null, "banco fechado");
      }catch(SQLException erroSQL){
          JOptionPane.showMessageDialog(null, "Não foi possível fechar o banco"+ erroSQL.getMessage());
          resul = false;
      } 
  }
   public void executeSQL(String sql){
      try
      {
          statement = conexao.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
          resultset = statement.executeQuery(sql);
      }catch(SQLException sqlex)
      {
          JOptionPane.showMessageDialog(null, sqlex.getMessage()+sql);
      }
   }

}[/code]

Esse é o código para inserir no banco:

[code] private void jb_salvarActionPerformed(java.awt.event.ActionEvent evt) {

    if ((tf_nome.getText().isEmpty() )){
            
    
        JOptionPane.showMessageDialog(null, "Os campos não podem retornar vazios");
    }
    else{ 
                
   try{
       String nome=("INSERT INTO cadastro_usuario (nome) VALUES  ('"+tf_nome.getText()+"')");
       c.statement.executeUpdate(nome);
       JOptionPane.showMessageDialog(null,"Usuário cadastrado com sucesso.");
       
       
   }
   catch (SQLException erro){
       JOptionPane.showMessageDialog(null,"Erro"+erro);
   }
    }      
   
}                                         [/code]

Esse é o erro que dá:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at cadastros.cadastro_usuario.jb_salvarActionPerformed(cadastro_usuario.java:215) at cadastros.cadastro_usuario.access$200(cadastro_usuario.java:14) at cadastros.cadastro_usuario$3.actionPerformed(cadastro_usuario.java:93) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018) at javax.swing.AbstractButton$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.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289) at java.awt.Component.processMouseEvent(Component.java:6505) at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) at java.awt.Component.processEvent(Component.java:6270) at java.awt.Container.processEvent(Container.java:2229) at java.awt.Component.dispatchEventImpl(Component.java:4861) at java.awt.Container.dispatchEventImpl(Container.java:2287) at java.awt.Component.dispatchEvent(Component.java:4687) 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:4687) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723) at java.awt.EventQueue.access$200(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:682) at java.awt.EventQueue$3.run(EventQueue.java:680) 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:696) at java.awt.EventQueue$4.run(EventQueue.java:694) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:693) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139) at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

Alguma sugestão? Algum erro no código ? Obrigado!

#2