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POInfinite Recursion with Jackson JSON and Hibernate JPA issue
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  1. POInfinite Recursion with Jackson JSON and Hibernate JPA issue
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    copied!<p>When trying to convert a JPA object that has a bi-directional association into JSON, I keep getting </p> <pre><code>org.codehaus.jackson.map.JsonMappingException: Infinite recursion (StackOverflowError) </code></pre> <p>All I found is <a href="http://forum.springsource.org/showthread.php?t=88803" rel="noreferrer">this thread</a> which basically concludes with recommending to avoid bi-directional associations. Does anyone have an idea for a workaround for this spring bug?</p> <p>------ EDIT 2010-07-24 16:26:22 -------</p> <p>Codesnippets:</p> <p>Business Object 1:</p> <pre><code>@Entity @Table(name = "ta_trainee", uniqueConstraints = {@UniqueConstraint(columnNames = {"id"})}) public class Trainee extends BusinessObject { @Id @GeneratedValue(strategy = GenerationType.TABLE) @Column(name = "id", nullable = false) private Integer id; @Column(name = "name", nullable = true) private String name; @Column(name = "surname", nullable = true) private String surname; @OneToMany(mappedBy = "trainee", fetch = FetchType.EAGER, cascade = CascadeType.ALL) @Column(nullable = true) private Set&lt;BodyStat&gt; bodyStats; @OneToMany(mappedBy = "trainee", fetch = FetchType.EAGER, cascade = CascadeType.ALL) @Column(nullable = true) private Set&lt;Training&gt; trainings; @OneToMany(mappedBy = "trainee", fetch = FetchType.EAGER, cascade = CascadeType.ALL) @Column(nullable = true) private Set&lt;ExerciseType&gt; exerciseTypes; public Trainee() { super(); } ... getters/setters ... </code></pre> <p>Business Object 2:</p> <pre><code>import javax.persistence.*; import java.util.Date; @Entity @Table(name = "ta_bodystat", uniqueConstraints = {@UniqueConstraint(columnNames = {"id"})}) public class BodyStat extends BusinessObject { @Id @GeneratedValue(strategy = GenerationType.TABLE) @Column(name = "id", nullable = false) private Integer id; @Column(name = "height", nullable = true) private Float height; @Column(name = "measuretime", nullable = false) @Temporal(TemporalType.TIMESTAMP) private Date measureTime; @ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL) @JoinColumn(name="trainee_fk") private Trainee trainee; </code></pre> <p>Controller:</p> <pre><code>import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; import javax.servlet.http.HttpServletResponse; import javax.validation.ConstraintViolation; import java.util.*; import java.util.concurrent.ConcurrentHashMap; @Controller @RequestMapping(value = "/trainees") public class TraineesController { final Logger logger = LoggerFactory.getLogger(TraineesController.class); private Map&lt;Long, Trainee&gt; trainees = new ConcurrentHashMap&lt;Long, Trainee&gt;(); @Autowired private ITraineeDAO traineeDAO; /** * Return json repres. of all trainees */ @RequestMapping(value = "/getAllTrainees", method = RequestMethod.GET) @ResponseBody public Collection getAllTrainees() { Collection allTrainees = this.traineeDAO.getAll(); this.logger.debug("A total of " + allTrainees.size() + " trainees was read from db"); return allTrainees; } } </code></pre> <p>JPA-implementation of the trainee DAO:</p> <pre><code>@Repository @Transactional public class TraineeDAO implements ITraineeDAO { @PersistenceContext private EntityManager em; @Transactional public Trainee save(Trainee trainee) { em.persist(trainee); return trainee; } @Transactional(readOnly = true) public Collection getAll() { return (Collection) em.createQuery("SELECT t FROM Trainee t").getResultList(); } } </code></pre> <p>persistence.xml</p> <pre><code>&lt;persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"&gt; &lt;persistence-unit name="RDBMS" transaction-type="RESOURCE_LOCAL"&gt; &lt;exclude-unlisted-classes&gt;false&lt;/exclude-unlisted-classes&gt; &lt;properties&gt; &lt;property name="hibernate.hbm2ddl.auto" value="validate"/&gt; &lt;property name="hibernate.archive.autodetection" value="class"/&gt; &lt;property name="dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/&gt; &lt;!-- &lt;property name="dialect" value="org.hibernate.dialect.HSQLDialect"/&gt; --&gt; &lt;/properties&gt; &lt;/persistence-unit&gt; &lt;/persistence&gt; </code></pre>
 

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