Erro ao tentar se conectar ao Banco de Dados

Olá à todos.,

De um dia para o outro não consigo pegar os dados do BD.

Tentei me conectar pelo cmd do sql e consegui, nesse cmd não apresenta nenhum erro só no eclipse.

O código:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;

public class Conexao {

    public Conexao() {

    }

    public ObservableList<Person> listaDeContas(int type) {
        ObservableList<Person> contas = FXCollections.observableArrayList();

        String query = "SELECT NOME,DIVIDA,PAGAMENTO,DATADV FROM " + (type==0 ? "CLIENTES" : "TABLECARNE");
        System.out.println(query);

        String url = "Jdbc:oracle:thin:@localhost:1521:xe";
        try (Connection con = DriverManager.getConnection(url, "system", "AL0921069LLUCASJL");
                PreparedStatement stm = con.prepareStatement(query);
                ResultSet rs = stm.executeQuery()) {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            while (rs.next()) {
                String nome = rs.getString("NOME");
                String divida = rs.getString("DIVIDA");
                String pagamento = rs.getString("PAGAMENTO");
                String dataDv = rs.getString("DATADV");

                contas.addAll(new Person(nome, divida, pagamento, Person.validaVencimentos(dataDv, type).toString()));
            }
        } catch (Exception es) {
            es.printStackTrace();
        }

         return contas;
    }

    public static void main(String[] args) {
        new Conexao().listaDeContas(0).forEach((obs)->System.out.println(obs.getVencimento()));
    }

}

E dá esse erro:

java.sql.SQLException: Erro de ES: The Network Adapter could not establish the connection
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:419)
    at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:536)
    at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:228)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at pc.sco.sc.Conexao.listaDeContas(Conexao.java:24)
    at pc.sco.sc.Conexao.main(Conexao.java:47)
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
    at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:375)
    at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:422)
    at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:678)
    at oracle.net.ns.NSProtocol.connect(NSProtocol.java:238)
    at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1054)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:308)
    ... 8 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:201)
    at oracle.net.nt.ConnOption.connect(ConnOption.java:123)
    at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:353)
    ... 13 more

O que faço?