cannot instatiate abstract class

[jflf83]

Hello, I have problems when a I try to list the elements of an abstract class. the exceptions is:
Caused by: javax.ejb.EJBTransactionRolledbackException: javax.persistence.Persis

import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
public abstract class Y extends X{

public Saida()
{
super();
}

public Saida(double consumoFinanceiro, Setor setor)
{
super(consumoFinanceiro, setor);
}



}

package br.gov.gemog.siest.core.entity;

import javax.persistence.Entity;
import javax.persistence.ManyToOne;
import javax.persistence.Transient;

@Entity
public class Z extends X
{
public static final String ENTRADA = "Entrada";

private String numeroNotaFiscal;

private Fornecedor fornecedor;

private double valorEntrada;

private String codigoFornecedor;


public double getValorEntrada() {
return valorEntrada;
}

public void setValorEntrada(double valorEntrada) {
this.valorEntrada = valorEntrada;
}

@Override
public String getNumeroNotaFiscal()
{
return numeroNotaFiscal;
}

public void setNumeroNotaFiscal(String numeroNotaFiscal)
{
this.numeroNotaFiscal = numeroNotaFiscal;
}

public void setFornecedor(Fornecedor fornecedor)
{
this.fornecedor = fornecedor;
}

@ManyToOne
public Fornecedor getFornecedor()
{
return fornecedor;
}

public String getCodigoFornecedor() {
return codigoFornecedor;
}

public void setCodigoFornecedor(String codigoFornecedor) {
this.codigoFornecedor = codigoFornecedor;
}

@Override
@Transient
public String getTipoMovimentacao()
{
return ENTRADA;
}

@Override
@Transient
public String getValorMovimentacao()
{
return SEM_ELEMENTO;
}

@Override
@Transient
public Object getSetor()
{
return " - ";
}

@Override
@Transient
public double getConsumoFinanceiro() {
// TODO Auto-generated method stub
return 0;
}
}

Someone can help me?
Thank you