Erro java.lang.NullPointerException

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HTTP Status 500 -

type Exception report

message

description The server encountered an internal error that prevented it from fulfilling this request.

exception

java.lang.NullPointerException

br.com.atividade1.dao.UsuarioDao.cadastraUsuario(UsuarioDao.java:41)

br.com.atividade1.controller.CadastrarUsuario.processRequest(CadastrarUsuario.java:38)

br.com.atividade1.controller.CadastrarUsuario.doPost(CadastrarUsuario.java:46)

javax.servlet.http.HttpServlet.service(HttpServlet.java:646)

javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.56 logs.

private int id;
private int tipo;
private int nivel;
private String matricula;
private String login;
private String senha;

import java.sql.Connection;

import java.sql.SQLException;

import br.com.atividade1.connection.factory.Conexao;

import br.com.atividade1.javabean.model.UsuarioBean;

import java.sql.PreparedStatement;

import java.util.logging.Level;

import java.util.logging.Logger;

private Connection con;

public UsuarioDao() {
    this.con = new Conexao().getConnection();

}
 UsuarioBean usuario = new UsuarioBean();

public void cadastraUsuario(UsuarioBean usuario) throws SQLException {
    String sql = " insert into cadastro_usuario values(?,?,?,?,?,?)";

    PreparedStatement ps = null;
    try {
        ps = con.prepareStatement(sql);
     
        ps.setInt(1, 0);
        ps.setInt(2, usuario.getTipo());
        ps.setInt(3, usuario.getNivel());
        ps.setString(4, usuario.getMatricula());
        ps.setString(5, usuario.getLogin());
        ps.setString(6, usuario.getSenha());
      
        ps.execute();
        
    } catch (SQLException ex) {
        Logger.getLogger(UsuarioDao.class.getName()).log(Level.SEVERE, null, ex);
    } finally {
        con.close();
        ps.close();
    }
}

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import br.com.atividade1.javabean.model.UsuarioBean;

import br.com.atividade1.dao.UsuarioDao;

import java.sql.SQLException;

import java.util.logging.Level;

import java.util.logging.Logger;

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException, SQLException {
    
    String tipo = request.getParameter("tipo");
    String nivel = request.getParameter("nivel");
    String matricula = request.getParameter("matricula");
    String login = request.getParameter("login");
    String senha = request.getParameter("senha");
  
    UsuarioBean usuario_bean = new UsuarioBean();

  
    usuario_bean.setTipo(Integer.parseInt(tipo));
    usuario_bean.setNivel(Integer.parseInt(nivel));
    usuario_bean.setMatricula(matricula);
    usuario_bean.setLogin(login);
    usuario_bean.setSenha(senha);
 

    UsuarioDao usuario_dao = new UsuarioDao();
    usuario_dao.cadastraUsuario(usuario_bean);
    request.getRequestDispatcher("testeCadastro.jsp").forward(request, response);
}

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    try {
        processRequest(request, response);
        request.setAttribute("msg", "Dados Gravados!");
        request.getRequestDispatcher("testeCadastro.jsp").forward(request, response);
    } catch (SQLException ex) {
        Logger.getLogger(CadastrarUsuario.class.getName()).log(Level.SEVERE, null, ex);
        request.setAttribute("msg", "Dados Não Gravados!");
        request.getRequestDispatcher("testeCadastro.jsp").forward(request, response);
    }
}