Erro javax.servlet.ServletException: java.lang.OutOfMemoryError

package com.br.dao;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class ManagerEntityManager {
	
	EntityManagerFactory factory;
	EntityManager entityManager;

	/* Metodo de Criação do Entity Manager */
	private EntityManager geraEntityManager(){
		
		factory = Persistence.createEntityManagerFactory("Portal");
		
		if (entityManager == null){
			entityManager = factory.createEntityManager();
		}
		
		if (!factory.isOpen()) {
			System.out.println("Nova conexão");
			entityManager = factory.createEntityManager();
			return entityManager;
		}else{
			System.out.println("Utilizando conexão já aberta");
			return entityManager;
		}
	}
	
	public EntityManager getEntityManager(){
		return geraEntityManager();
	}
}

package com.br.dao;

import java.util.List;
import java.util.logging.Logger;

import javax.persistence.EntityManager;
import javax.persistence.Query;

import com.br.model.Ts_Local_Negocio;

public class Ts_Local_NegocioDao {
	
	Logger logger = Logger.getLogger("br.com.log");  
	
	/* Metodo de Cria��o do Entity Manager */
	private EntityManager getEntityManager(){
		/*
		EntityManagerFactory factory;
		EntityManager entityManager;
		
		factory = Persistence.createEntityManagerFactory("Portal");
		
		if (factory.isOpen()) {
			factory.close();
			entityManager = factory.createEntityManager();
		}else{
			entityManager = factory.createEntityManager();
		}
		
		return entityManager;
		*/
		ManagerEntityManager manager = new ManagerEntityManager();
		return manager.getEntityManager();
	}
	
	/* Metodo de consulta no banco de dados */
	private List<Ts_Local_Negocio> consultar(List<String> pColunas, List<String> pValores){
		
		EntityManager entityManager = getEntityManager();
		String vSQL = "from Ts_Local_Negocio as ts_local_negocio";
		
		if (pColunas != null){
			vSQL += " WHERE ";
			
			for (int i = 0; i < pColunas.size(); i++){
				if (i==0){
					vSQL += " " + pColunas.get(i).toString() + " = '" + pValores.get(i).toString() + "'";
				}else{
					vSQL += " AND " + pColunas.get(i).toString() + " = '" + pValores.get(i).toString() + "'";
				}
			}
		}
		
		vSQL += " ORDER BY NUM_ID DESC";
		logger.info("Consulta : " + vSQL);
		Query vQuery = entityManager.createQuery(vSQL);		
		@SuppressWarnings("unchecked")
		List<Ts_Local_Negocio> listaLocalNegocio = vQuery.getResultList();
		entityManager.close();
		return listaLocalNegocio;		
	}	
	
	public List<Ts_Local_Negocio> select(List<String> pColunas, List<String> pValores){
		return consultar(pColunas,pValores);
	}

}