// Conectar
public String conectarDB() {

// Variáveis
String driver = "org.postgresql.Driver";
String dbURL = "jdbc:postgresql://localhost:5432/database";
String user = "postgres";
String pass = "123456";

try{

    //Carrega o driver
    Class.forName(driver);
    Connection conn = DriverManager.getConnection(dbURL, user, pass);
    return "Conexão: Ok!";

} catch(ClassNotFoundException e) {
    e.printStackTrace();
    return "Conexão: Erro Driver!";

} catch (SQLException e) {
    e.printStackTrace();
    return "Conexão: Erro Database!";
}