Erro ao executar aplicação web

Programação Java
#1

No meu computador está instalado windows xp, tomcat 6.0.18 e java 6.0.15. Instalei minha aplicação web com o framework zk e ela funciona normalmente com o mysql 5 e conector mysql 5.1.6. Quando copiei essa aplicação para o meu servidor web hospedado em um dns especifico, a aplicação apresenta um erro Execução Desconhecida:java.lang.NullPointerException. Abri o arquivo catalina.out que possui entre outros erros, os seguintes:
Feb 23, 2009 10:59:19 AM org.zkoss.zk.ui.impl.UiEngineImpl handleError:1107
SEVERE: >>java.lang.NullPointerException

at AgendaEletronicaMVC.DAO.AgendaDAO.listaAgendaAll(AgendaDAO.java:19)
at AgendaEletronicaMVC.controle.AgendaControle.preencheListaPesqAgenda(AgendaControle.java:89)
at AgendaEletronicaMVC.controle.AgendaControle.onCreate(AgendaControle.java:81)
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 org.zkoss.zk.ui.impl.EventProcessor.process0(EventProcessor.java:213)
at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:143)
at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.process0(EventProcessingThreadImpl.java:488)
…

Não sei como resolver… alguem me ajude…
grato pela atenção.

#2

oque tem na linha 19 da AgendaDAO?
algo ali está vindo null

#3

O inicio do método tem o seguinte:

Agenda a;
    Vector v = new Vector();
    Connection conn= conexao.abreConexaoBD();
    ResultSet rs = null;
    Statement st = conn.createStatement();
    rs= st.executeQuery("select * from agenda order by nome");

será que tenho que é o caso de inserir null para Statement st?

#4

Tem dados a base!!? O Driver ta vindo carregado!?
Qual é a linha 19!?
t+ 8)

#5

pega exatamente alinha 19
clica ali no erro que ele vai pra linha 19 do seu codigo
ai cola aqui sua classe e indique qual é a linha 19 do codigo que ele está acusando o erro
pra poder ver aonde ta dando a excessão certinho

#6

A linha 19 é a

Statement st = conn.createStatement();

O engraçado é que no meu computador, com windows xp + tomcat 6.0.18 + mysql + conector 6.1.5 funciona normalmente.
Mas, quando envio para o meu servidor, na minha hospedagem para o teste que é em linux, ocorre o referido erro.
Não estou entendendo.
Grato pela atenção.

#7

Seu objeto ‘conn’ está nulo. Onde ele é instanciado?

#8

o erro agora está ocorrendo na linha 21.Corrigi o código inseri algumas linhas.
No meu computador executa normal.
Mas o erro continua ocorrendo no servidor da minha hospedagem.
ACESSE O ENDEREÇO http://www.vpcamargo.kinghost.net/AgEletronicaMVC/index.zul e veja o que ocorre.
A aplicação aparece normalmente, mas quando se ativa o cadastro de agenda, aparece o erro, mas a tela
aparece sem os dados.

Segue os erros encontrados no catalina.out.
Parei o servidor, inseri as mudanças e iniciei o tomcat novamente:

Feb 24, 2009 12:08:04 AM org.apache.catalina.startup.HostConfig checkResources
INFO: Undeploying context [/AgEletronicaMVC]
The event processing thread stops
Feb 24, 2009 12:12:34 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:12:34 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:12:44 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:12:44 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:12:54 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added : ‘Filters.jar’
Feb 24, 2009 12:12:54 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:04 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:04 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:14 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:14 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:24 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:24 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:34 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:34 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:44 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:44 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:13:54 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:13:54 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:04 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:04 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:14 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:14 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:24 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:24 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:34 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:34 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:44 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:44 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:14:54 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:14:54 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:04 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:15:04 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:14 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:15:14 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:24 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:15:24 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:34 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:15:34 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:44 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added
Feb 24, 2009 12:15:44 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:15:54 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added : ‘zk.jar’
Feb 24, 2009 12:15:54 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:16:05 AM org.apache.catalina.loader.WebappClassLoader modified
INFO: Additional JARs have been added : ‘zul.jar’
Feb 24, 2009 12:16:05 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Feb 24, 2009 12:16:05 AM org.zkoss.zk.ui.sys.ConfigParser parseConfigXml:125
INFO: Loading system default
Feb 24, 2009 12:17:52 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/java/jdk1.6.0_05/jre/lib/i386/server:/usr/java/jdk1.6.0_05/jre/lib/i386:/usr/java/jdk1.6.0_05/jre/…/lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib
Feb 24, 2009 12:17:52 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-10010
Feb 24, 2009 12:17:52 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 338 ms
Feb 24, 2009 12:17:52 AM org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
Feb 24, 2009 12:17:52 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.10
Feb 24, 2009 12:17:52 AM org.zkoss.zk.ui.sys.ConfigParser parseConfigXml:125
INFO: Loading system default
Feb 24, 2009 12:17:53 AM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
Feb 24, 2009 12:17:53 AM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()
Feb 24, 2009 12:17:53 AM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: attributeAdded(‘org.apache.catalina.Registry’, ‘org.apache.tomcat.util.modeler.Registry@b1a4e2’)
Feb 24, 2009 12:17:53 AM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: attributeAdded(‘org.apache.catalina.MBeanServer’, ‘com.sun.jmx.mbeanserver.JmxMBeanServer@c00025’)
Feb 24, 2009 12:17:53 AM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-10010
Feb 24, 2009 12:17:53 AM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:10011
Feb 24, 2009 12:17:53 AM org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/17 config=null
Feb 24, 2009 12:17:53 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 1153 ms
Feb 24, 2009 12:18:23 AM org.zkoss.zk.ui.impl.UiEngineImpl handleError:1107
SEVERE: >>java.lang.NullPointerException

at AgendaEletronicaMVC.DAO.AgendaDAO.listaAgendaAll(AgendaDAO.java:21)
at AgendaEletronicaMVC.controle.AgendaControle.preencheListaPesqAgenda(AgendaControle.java:89)
at AgendaEletronicaMVC.controle.AgendaControle.onCreate(AgendaControle.java:81)
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 org.zkoss.zk.ui.impl.EventProcessor.process0(EventProcessor.java:213)
at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:143)
at org.zkoss.zk.ui.impl.EventProcessingThreadImpl.process0(EventProcessingThreadImpl.java:488)
…

pedaço da classe AgendaDAO:

01 package AgendaEletronicaMVC.DAO;
02
03 import AgendaEletronicaMVC.modelo.;
04 import java.sql.;
05 import com.mysql.jdbc.Connection;
06 import java.util.Vector;
07
08 public class AgendaDAO {
09 public Conexao conexao = new Conexao();
10
11
12 // TABELA AGENDA - METODOS DE PERSISTENCIA - INICIO
12 public Vector listaAgendaAll() throws SQLException
14 {
15 Agenda a;
16 Vector v = new Vector();
17 Connection conn = null;
18 conn= conexao.abreConexaoBD();
19 ResultSet rs = null;
20 Statement st = null;
21 st = conn.createStatement();
22 rs= st.executeQuery(“select * from agenda order by nome”);
…
Corrige o código, inserindo a linha 17 (Connection conn = null).

a conexão ocorre na classe Conexao (que está instanciada na linha 09) através
do método abreConexao (na linha 18).
A classe Conexao é a seguinte:

package AgendaEletronicaMVC.DAO;

import java.sql.*;
import java.sql.DriverManager;
import com.mysql.jdbc.Connection;

public class Conexao
{
//usuário e senha
private String login = “root”;
private String senha = “”;
// IP do servidor do banco
private String host = “localhost”;
// Nome do banco de dados
private String dbName = “vpcamargo”;
// URL de conexao do banco
private String url = “jdbc:mysql://” + host + “/” + dbName;
// Objeto do tipo Connection para estabelecer a conexão
public Connection conexao = null;
// Objeto Statement usado para enviar consultas para o banco de dados
public Statement stmt = null;
public ResultSet r = null;
public Conexao() { }

public Connection abreConexaoBD()
{
try
{
try
{
Class.forName(“com.mysql.jdbc.Driver”);
}
catch (ClassNotFoundException ex)
{
return null;
}
try
{
// efetua conexao com o banco de dados
this.conexao =
(Connection) DriverManager.getConnection(url,login,senha);
}
catch (SQLException ex)
{
return null;
}
return this.conexao;
}
catch (Exception e)
{
return null;
}
}
}

#9