How to convert bean with reference bean to json in java?

Question

I am trying to convert my bean to json via Gson. My bean (Logs) include another bean(Log) and second bean reference to first bean.

@Entity
@Table(name = "t_logs")
public class Logs {

    @Id
    @Column(name = "executionid")
    private String executionId;

    @Column(name = "sentdate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date sentDate;

    @Column(name = "sent")
    private boolean sent;

    @OneToMany(mappedBy = "logs", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    private List<Log> logList;}


@Entity
@Table(name = "t_log")
public class Log {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private long id;

    @ManyToOne
    @JoinColumn(name = "executionid")
    private Logs logs;

    @Column(name = "startdate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date startDate;

    @Column(name = "enddate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date endDate;
    }

So when I try to convert Json format, I getting an error like above; java.lang.StackOverflowError

I think this is a cycle but how can I resolve it, I don't know

        Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ").create();
        return gson.toJson(logs, Logs.class);

Answer 1

I know that is the worst but I could not find any way!

private String convertToMyJSON(Logs logs) {

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");

    String jsonObject = "{"
            + "\"executionId\":\"" + logs.getExecutionId() + "\","
            + "\"startDate\":\"" + sdf.format(logs.getStartDate()) + "\","
            + "\"logList\":[" + getLogString(logs) + "]"
            + "}";

    return jsonObject;
}

private String getLogString(Logs logs) {

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");

    String logString = "";

    for (Log l : logs.getLogList()) {

        logString = logString
                + "{"
                + "\"id\":" + l.getId() + ","
                + "\"executionId\":\"" + logs.getExecutionId() + "\","
                + "\"startDate\":\"" + sdf.format(l.getStartDate()) + "\","
                + "\"endDate\":\"" + sdf.format(l.getEndDate()) + "\","
                + "},";
    }

    return logString.substring(0, logString.lastIndexOf(","));
}