Alguém pode me ajudar? Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

[details=Erro]Exception in thread “AWT-EventQueue-0” java.lang.NullPointerException

at Principal.CConexao.sqlExecuta(CConexao.java:42)

at Principal.CAgenda.BuscaMedico(CAgenda.java:28)

at Principal.CAgenda.Salvar(CAgenda.java:54)

at Principal.JAgenda.jButtonConcluirActionPerformed(JAgenda.java:222)

at Principal.JAgenda.access$300(JAgenda.java:20)

at Principal.JAgenda$4.actionPerformed(JAgenda.java:113)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)

at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)

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.Component.processMouseEvent(Component.java:6533)

at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)

at java.awt.Component.processEvent(Component.java:6298)

at java.awt.Container.processEvent(Container.java:2236)

at java.awt.Component.dispatchEventImpl(Component.java:4889)

at java.awt.Container.dispatchEventImpl(Container.java:2294)

at java.awt.Component.dispatchEvent(Component.java:4711)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)

at java.awt.Container.dispatchEventImpl(Container.java:2280)

at java.awt.Window.dispatchEventImpl(Window.java:2746)

at java.awt.Component.dispatchEvent(Component.java:4711)

at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)

at java.awt.EventQueue.access$500(EventQueue.java:97)

at java.awt.EventQueue$3.run(EventQueue.java:709)

at java.awt.EventQueue$3.run(EventQueue.java:703)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)

at java.awt.EventQueue$4.run(EventQueue.java:731)

at java.awt.EventQueue$4.run(EventQueue.java:729)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)

at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

CONSTRUÍDO COM SUCESSO (tempo total: 44 segundos)

[/details]

[details=O codigo da parte de conexão SQL aonde é citado no erro:]public void sqlExecuta(String sql){

try {

atm= con.createStatement(rs.TYPE_SCROLL_INSENSITIVE,rs.CONCUR_READ_ONLY);

// codigo acima, vai diferir a diferença do maiúscuo para o minusculo e dps vai percorrer tanto do inicio para o fim tando fim fim para o inicio.

rs=atm.executeQuery(sql);

} catch (SQLException ex) {

JOptionPane.showMessageDialog(null,“Erro ao executar sql”+ex.getMessage());

}

}[/details]

[details=A classe da agenda responsavel por ficar os metodos:(Apesar de o erro acusar apenas dentro do Metodo BuscaMedico (serve para pegar o codigo do medico))]public class CAgenda {

MAgenda agenda= new MAgenda();

CConexao cone= new CConexao();

CConexao conepaciente= new CConexao();

CConexao conemedico= new CConexao();

int codMed;

int codPac;

public void BuscaMedico(String nomeMedico){
conemedico.conexao();
cone.sqlExecuta("select *from medicos where nome_medico='"+nomeMedico+"'");
    try {
        cone.rs.first();
        codMed= cone.rs.getInt("id_medico");
    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, "Erro  ao buscar medico \nErro:"+ex);
    }


conemedico.desconecta();
}
public void BuscaPaciente(String nomePaciente){
conepaciente.conexao();
cone.sqlExecuta("select *from pacientes where nome_paciente='"+nomePaciente+"'");
    try {
        cone.rs.first();
        codPac= cone.rs.getInt("id_paciente");
    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, "Erro  ao buscar Paciente \nErro:"+ex);
    }


conemedico.desconecta();
}

public void Salvar(MAgenda agenda){// pega por parametro do pesquisar
BuscaMedico(agenda.getNomeMedico());
BuscaPaciente(agenda.getNomePac());
    cone.conexao();
    try {
        PreparedStatement pst = cone.con.prepareStatement("insert into agendamento(agenda_codpac, agenda_codmedico, agenda_motivo, agenda_turno, agenda_data, agenda_status)values (?,?,?,?,?,?)");
        pst.setInt(1, codMed);
        pst.setInt(2, codMed);
        pst.setString(3, agenda.getMovito());
        pst.setString(4, agenda.getTurno());
        pst.setString(5, agenda.getData());
        pst.setString(6, agenda.getStatus());
        pst.execute();
    } catch (SQLException ex) {
        Logger.getLogger(CAgenda.class.getName()).log(Level.SEVERE, null, ex);
        JOptionPane.showMessageDialog(null, "Erro ao inserir dados \n ERRO:"+ex);
    }
    cone.desconecta();
}