Question

I want to create a table, where the id is come strings composed. This is how I did is following some examples and documentation:

       @Entity
@Table(name = "media_locator")
public class MediaLocator {

    private List<MediaObject> mediaObjects;
    private MediaLocatorPK primaryKey = new MediaLocatorPK();

//    @Id
//    @GeneratedValue(strategy = GenerationType.AUTO)
//    @Column(name = "id", unique = true, nullable = false)
//    public int getId() {
//        return id;
//    }
//
//    public void setId(int id) {
//         this.id = id;
//    }

    @EmbeddedId
    public MediaLocatorPK getPrimaryKey() {
        return primaryKey;
    }

    public void setPrimaryKey(MediaLocatorPK primaryKey) {
        this.primaryKey = primaryKey;
    }



//    @Column(name = "location", length = 200)
    public String getLocation() {
        return primaryKey.getLocation();
    }


    public void setLocation(String location) {
        this.primaryKey.setLocation(location);
    }

//    @Column(name = "description", length = 200, nullable = false)
    public String getDescription() {
        return primaryKey.getDescription();
    }

    public void setDescription(String description) {
        this.primaryKey.setDescription(description);
    }


//    @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.LAZY, mappedBy="mediaLocator")    
//    public List<MediaObject> getMediaObjects() {
//        return mediaObjects;
//    }
//
//    public void setMediaObjects(List<MediaObject> mediaObjects) {
//         mediaObjects = mediaObjects;
//    }


    @ManyToMany(
            cascade={CascadeType.ALL},  
            fetch=FetchType.LAZY)
    @JoinTable(name = "media_object_location", 
            joinColumns=@JoinColumn(name="mediaLocator_id"),
            inverseJoinColumns=@JoinColumn(name="mediaObject_id"))  
    public List<MediaObject> getMediaObjects() {
        return mediaObjects;
    }

    public void setMediaObjects(List<MediaObject> mediaObjects) {
        this.mediaObjects = mediaObjects;
    }


//    @Column(name = "protocol", length = 200, nullable = false)
    public String getProtocol() {
        return primaryKey.getProtocol();
    }

    public void setProtocol(String protocol) {
        this.primaryKey.setProtocol(protocol);
    }
//    @Column(name = "host", length = 200, nullable = false)
    public String getHost() {
        return primaryKey.getHost();
    }

    public void setHost(String host) {
        this.primaryKey.setHost(host);
    }
//    @Column(name = "port", length = 200, nullable = false)
    public String getPort() {
        return primaryKey.getPort();
    }

    public void setPort(String port) {
        this.primaryKey.setPort(port);
    }
//    @Column(name = "path", length = 200, nullable = false)
    public String getPath() {
        return primaryKey.getPath();
    }

    public void setPath(String path) {
        this.primaryKey.setPath(path);
    }

@Embeddable class MediaLocatorPK implements Serializable
{
  private String location;
  private String description;
  private String protocol;
  private String host;
  private String port;
  private String path;

    public String getLocation() {
        return location;
    }
    public void setLocation(String location) {
        this.location = location;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public String getProtocol() {
        return protocol;
    }
    public void setProtocol(String protocol) {
        this.protocol = protocol;
    }
    public String getHost() {
        return host;
    }
    public void setHost(String host) {
        this.host = host;
    }
    public String getPort() {
        return port;
    }
    public void setPort(String port) {
        this.port = port;
    }
    public String getPath() {
        return path;
    }
    public void setPath(String path) {
        this.path = path;
    }


}

Before, I had an id auto generated, and each atribute had a colum in the table, @Column(name = "location", length = 200), for instance.

In this way I can not store the data due to referencies from relations with other objects

Caused by: org.hibernate.AnnotationException: A Foreign key refering com.app.MediaLocator from com.app.MediaObject has the wrong number of column. should be 6
    at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:429)
    at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1443)
    at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1262)
    at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:693)
    at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:628)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:65)
    at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1686)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1393)
    at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1345)
    at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:717)
    at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1469)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1409)

This specific relation is:

@ManyToMany(
            cascade={CascadeType.ALL},  
            fetch=FetchType.LAZY)
    @JoinTable(name = "media_object_location", 
            joinColumns=@JoinColumn(name="mediaLocator_id"),
            inverseJoinColumns=@JoinColumn(name="mediaObject_id"))  
    public List<MediaObject> getMediaObjects() {
        return mediaObjects;
    }

    public void setMediaObjects(List<MediaObject> mediaObjects) {
        this.mediaObjects = mediaObjects;
    }

And from mediaObject side:

@ManyToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, fetch = FetchType.LAZY, mappedBy = "mediaObjects")
    public List<MediaLocator> getMediaLocators() {
        return mediaLocators;
    }

    public void setMediaLocators(List<MediaLocator> mediaLocators) {
        this.mediaLocators = mediaLocators;
    }

what am I doing wrong?

Thanks in advance

Answer 1

Once you have moved properties to the embeddable class you need to remove them from the main class, there will be just one reference of your embedded class, so in your example you need to remove all properties like location from your MediaLocator class.

Also what is property id doing in your MediaLocator ? Since there is no specific column annotation in your class hibernate will try to map each and every attribute to the table column, it will succeed in that mapping if the naming of both the property and table column are same.

If you dont need id then either remove it or mark it as @Transient.

This piece of code will reproduce the same error what you are getting.

Student Class

package com.mumz.test.jpa.embedded.manytomany;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="STUDENT")
public class StudentMTM {

    private StudentMTMPK    studentPK   = null;
    private Set<Address>      address     = null;

    public StudentMTM(StudentMTMPK studentPK, Set<Address> address) {
        super();
        this.studentPK = studentPK;
        this.address = address;
    }

    /**
     * @return the id
     */
    public Integer getId() {
        return studentPK.getId();
    }

    /**
     * @param id the id to set
     */
    public void setId(Integer id) {
        studentPK.setId(id);
    }

    /**
     * @return the name
     */
    public String getName() {
        return studentPK.getName();
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        studentPK.setName(name);
    }
    /**
     * @param studentPK
     *            the studentPK to set
     */
    public void setStudentPK(StudentMTMPK studentPK) {
        this.studentPK = studentPK;
    }

    /**
     * @param address
     *            the address to set
     */
    public void setAddress(Set<Address> address) {
        this.address = address;
    }

    /**
     * @return the address
     */
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "STUDENT_ADDRESS", joinColumns =
        {
            @JoinColumn(name = "STUDENT_ID")
        }, inverseJoinColumns =
        {
            @JoinColumn(name = "ADDRESS_ID")
        })
    public Set<Address> getAddress() {
        return address;
    }

    /**
     * @return the studentPK
     */
    @Id
    public StudentMTMPK getStudentPK() {
        return studentPK;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((studentPK == null) ? 0 : studentPK.hashCode());
        result = prime * result + ((address == null) ? 0 : address.hashCode());
        return result;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof StudentMTM)) {
            return false;
        }
        StudentMTM other = (StudentMTM) obj;
        if (studentPK == null) {
            if (other.studentPK != null) {
                return false;
            }
        } else if (!studentPK.equals(other.studentPK)) {
            return false;
        }
        if (address == null) {
            if (other.address != null) {
                return false;
            }
        } else if (!address.equals(other.address)) {
            return false;
        }
        return true;
    }
}

Student PK Class:

package com.mumz.test.jpa.embedded.manytomany;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
public class StudentMTMPK implements Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 3686950547855931594L;
    private Integer id = null;
    private String name = null;

    public StudentMTMPK(Integer id, String name) {
        this.id = id;
        this.name = name;
    }

    /**
     * @return the id
     */
    @Column(name="STUDENT_ID")
    public Integer getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * @return the name
     */
    @Column(name="STUDENT_NAME")
    public String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof StudentMTMPK)) {
            return false;
        }
        StudentMTMPK other = (StudentMTMPK) obj;
        if (id == null) {
            if (other.id != null) {
                return false;
            }
        } else if (!id.equals(other.id)) {
            return false;
        }
        if (name == null) {
            if (other.name != null) {
                return false;
            }
        } else if (!name.equals(other.name)) {
            return false;
        }
        return true;
    }
}

Address Class

package com.mumz.test.jpa.embedded.manytomany;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="ADDRESS")
public class Address {
    private Integer id = null;
    private String addressDetails = null;

    /**
     * @return the id
     */
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="ADDRESS_ID")
    public Integer getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * @return the addressDetails
     */
    @Column(name="ADDRESS_DETAILS")
    public String getAddressDetails() {
        return addressDetails;
    }

    /**
     * @param addressDetails the addressDetails to set
     */
    public void setAddressDetails(String addressDetails) {
        this.addressDetails = addressDetails;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((addressDetails == null) ? 0 : addressDetails.hashCode());
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof Address)) {
            return false;
        }
        Address other = (Address) obj;
        if (addressDetails == null) {
            if (other.addressDetails != null) {
                return false;
            }
        } else if (!addressDetails.equals(other.addressDetails)) {
            return false;
        }
        if (id == null) {
            if (other.id != null) {
                return false;
            }
        } else if (!id.equals(other.id)) {
            return false;
        }
        return true;
    }
}

If you run this piece of code and try to save an instance of Address you will get

Exception in thread "main" javax.persistence.PersistenceException: [PersistenceUnit: myJPAService] Unable to configure EntityManagerFactory
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:378)
    at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:56)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:63)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:47)
    at com.mumz.test.jpa.embedded.manytomany.EmbeddableTestMainApp.main(EmbeddableTestMainApp.java:9)
Caused by: org.hibernate.AnnotationException: A Foreign key refering com.mumz.test.jpa.embedded.manytomany.StudentMTM from com.mumz.test.jpa.embedded.manytomany.Address has the wrong number of column. should be 2
    at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:429)
    at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1460)
    at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1279)
    at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:710)
    at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:645)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:65)
    at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1716)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1423)
    at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1375)
    at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1519)
    at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:193)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:1100)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:282)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:366)

My manytomany in StudentMTM is broken.

Now this piece will work as it should be:

Student Class

package com.mumz.test.jpa.embedded.manytomany;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="STUDENT")
public class StudentMTM {

    private StudentMTMPK    studentPK   = null;
    private Integer id = null;
    private Set<Address>      address     = null;

    public StudentMTM(StudentMTMPK studentPK, Set<Address> address) {
        super();
        this.studentPK = studentPK;
        this.address = address;
    }

    /**
     * @return the id
     */
    @Column(name="STUDENT_ID")
    public Integer getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * @return the name
     */
    public String getName() {
        return studentPK.getName();
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        studentPK.setName(name);
    }
    /**
     * @param studentPK
     *            the studentPK to set
     */
    public void setStudentPK(StudentMTMPK studentPK) {
        this.studentPK = studentPK;
    }

    /**
     * @param address
     *            the address to set
     */
    public void setAddress(Set<Address> address) {
        this.address = address;
    }

    /**
     * @return the address
     */
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "STUDENT_ADDRESS", joinColumns =
        {
            @JoinColumn(name = "STUDENT_ID")
        }, inverseJoinColumns =
        {
            @JoinColumn(name = "ADDRESS_ID")
        })
    public Set<Address> getAddress() {
        return address;
    }

    /**
     * @return the studentPK
     */
    @Id
    public StudentMTMPK getStudentPK() {
        return studentPK;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((studentPK == null) ? 0 : studentPK.hashCode());
        result = prime * result + ((address == null) ? 0 : address.hashCode());
        return result;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof StudentMTM)) {
            return false;
        }
        StudentMTM other = (StudentMTM) obj;
        if (studentPK == null) {
            if (other.studentPK != null) {
                return false;
            }
        } else if (!studentPK.equals(other.studentPK)) {
            return false;
        }
        if (address == null) {
            if (other.address != null) {
                return false;
            }
        } else if (!address.equals(other.address)) {
            return false;
        }
        return true;
    }
}

Student PK

package com.mumz.test.jpa.embedded.manytomany;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
public class StudentMTMPK implements Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 3686950547855931594L;
    private String name = null;

    public StudentMTMPK(String name) {
        this.name = name;
    }

    /**
     * @return the name
     */
    @Column(name="STUDENT_NAME")
    public String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof StudentMTMPK)) {
            return false;
        }
        StudentMTMPK other = (StudentMTMPK) obj;
        if (name == null) {
            if (other.name != null) {
                return false;
            }
        } else if (!name.equals(other.name)) {
            return false;
        }
        return true;
    }
}

Address Class – No change from the first version.

In the second version JoinColumn is part of Student and mapping knows where it is mapping to.