Hibernate: could not initialize proxy - no Session

Note: Before anyone complain about this is a duplicate, make sure to go through the content without judging by title. Also make sure to read your reference question and the answer carefully to see whether it is duplicate. As of my experience now, the issue in this question can happen under different environments. For an example, the answer for someone using the below code in jsp will be different, for someone using Spring will be different and for someone whose DB is small and eager load is fine will be different. And no, my situation is not any of them.

I am writing a REST api using Hibernateand Jersey. Please have a look at the below code.

VerificationCodeJSONService.java - The JSON Service class

@Path("/verificaion_code")
public class VerificationCodeJSONService {

    @GET
    @Path("/getAllVerificationCodes")
    @Produces(MediaType.APPLICATION_JSON)
    public List<VerificaionCode> getAllVerificationCodes() {

        VerificationCodeService verificationCodeService=new VerificationCodeService();
        List<VerificaionCode> list = verificationCodeService.getAllVerificationCodes();
        return list;
    }
}

VerificationCodeService.java - The Service Layer

public class VerificationCodeService {    

    private static VerificationCodeDAOInterface verificationCodeDAOInterface;

    public VerificationCodeService() {
        verificationCodeDAOInterface = new VerificationCodeDAOImpl();
    }

    public List<VerificaionCode> getAllVerificationCodes() {
        Session session = verificationCodeDAOInterface.openCurrentSession();
        Transaction transaction = null;

        List<VerificaionCode> verificaionCodes = new ArrayList<VerificaionCode>();

        try {
            transaction = verificationCodeDAOInterface.openTransaction(session);
            verificaionCodes = verificationCodeDAOInterface.getAllVerificationCodes(session);
            transaction.commit();
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            session.close();
        }

        return verificaionCodes;

    }
}

VerificationCodeDAOImpl.java - The database layer

public class VerificationCodeDAOImpl implements VerificationCodeDAOInterface{

    private static final SessionFactoryBuilder sessionFactoryBuilder = SessionFactoryBuilder.getInstance();

    @Override
    public List<VerificaionCode> getAllVerificationCodes(Session session) {
        List<VerificaionCode> verificaionCodes=(List<VerificaionCode>)session.createQuery("from VerificaionCode").list();
        return verificaionCodes;
    }
}

VerificationCode.java - The DAO layer

public class VerificaionCode implements java.io.Serializable {

    private Integer idverificaionCode;
    private Patient patient;
    private String code;
    private Date dateCreated;
    private Date lastUpdated;

    public VerificaionCode() {
    }

    public VerificaionCode(Patient patient, String code, Date lastUpdated) {
        this.patient = patient;
        this.code = code;
        this.lastUpdated = lastUpdated;
    }

    public VerificaionCode(Patient patient, String code, Date dateCreated, Date lastUpdated) {
        this.patient = patient;
        this.code = code;
        this.dateCreated = dateCreated;
        this.lastUpdated = lastUpdated;
    }

    public Integer getIdverificaionCode() {
        return this.idverificaionCode;
    }

    public void setIdverificaionCode(Integer idverificaionCode) {
        this.idverificaionCode = idverificaionCode;
    }

    public Patient getPatient() {
        return this.patient;
    }

    public void setPatient(Patient patient) {
        this.patient = patient;
    }

    public String getCode() {
        return this.code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public Date getDateCreated() {
        return this.dateCreated;
    }

    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }

    public Date getLastUpdated() {
        return this.lastUpdated;
    }

    public void setLastUpdated(Date lastUpdated) {
        this.lastUpdated = lastUpdated;
    }

}

Patient.java - The DAO layer

public class Patient  implements java.io.Serializable {

     private Integer idpatient;
     private DiabetesType diabetesType;
     private Language language;
     private String customId;
     private String diabetesOther;
     private String firstName;
     private String lastName;
     private String email;
     private Date dob;
     private String parentEmail;
     private String gender;
     private Date diagnosedDate;
     private Double height;
     private Double weight;
     private String heightUnit;
     private String weightUnit;
     private String theme;
     private String userName;
     private String password;
     private Date dateCreated;
     private Date lastUpdated;

    public Patient() {
    }


    public Patient(DiabetesType diabetesType, Language language, String customId, String firstName, String email, Date dob, String gender, String theme, String userName, String password, Date lastUpdated) {
        this.diabetesType = diabetesType;
        this.language = language;
        this.customId = customId;
        this.firstName = firstName;
        this.email = email;
        this.dob = dob;
        this.gender = gender;
        this.theme = theme;
        this.userName = userName;
        this.password = password;
        this.lastUpdated = lastUpdated;
    }

    public Integer getIdpatient() {
        return this.idpatient;
    }

    public void setIdpatient(Integer idpatient) {
        this.idpatient = idpatient;
    }
    public DiabetesType getDiabetesType() {
        return this.diabetesType;
    }

    public void setDiabetesType(DiabetesType diabetesType) {
        this.diabetesType = diabetesType;
    }
    public Language getLanguage() {
        return this.language;
    }

    public void setLanguage(Language language) {
        this.language = language;
    }
    public String getCustomId() {
        return this.customId;
    }

    public void setCustomId(String customId) {
        this.customId = customId;
    }
    public String getDiabetesOther() {
        return this.diabetesOther;
    }

    public void setDiabetesOther(String diabetesOther) {
        this.diabetesOther = diabetesOther;
    }
    public String getFirstName() {
        return this.firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return this.lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmail() {
        return this.email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
    public Date getDob() {
        return this.dob;
    }

    public void setDob(Date dob) {
        this.dob = dob;
    }
    public String getParentEmail() {
        return this.parentEmail;
    }

    public void setParentEmail(String parentEmail) {
        this.parentEmail = parentEmail;
    }
    public String getGender() {
        return this.gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }
    public Date getDiagnosedDate() {
        return this.diagnosedDate;
    }

    public void setDiagnosedDate(Date diagnosedDate) {
        this.diagnosedDate = diagnosedDate;
    }
    public Double getHeight() {
        return this.height;
    }

    public void setHeight(Double height) {
        this.height = height;
    }
    public Double getWeight() {
        return this.weight;
    }

    public void setWeight(Double weight) {
        this.weight = weight;
    }
    public String getHeightUnit() {
        return this.heightUnit;
    }

    public void setHeightUnit(String heightUnit) {
        this.heightUnit = heightUnit;
    }
    public String getWeightUnit() {
        return this.weightUnit;
    }

    public void setWeightUnit(String weightUnit) {
        this.weightUnit = weightUnit;
    }
    public String getTheme() {
        return this.theme;
    }

    public void setTheme(String theme) {
        this.theme = theme;
    }
    public String getUserName() {
        return this.userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return this.password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    public Date getDateCreated() {
        return this.dateCreated;
    }

    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }
    public Date getLastUpdated() {
        return this.lastUpdated;
    }

    public void setLastUpdated(Date lastUpdated) {
        this.lastUpdated = lastUpdated;
    }
}

Below are my Hibernate mapping files for the above POJOs

VerificaionCode.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- Generated Sep 23, 2016 3:21:00 PM by Hibernate Tools 4.3.1 -->
<hibernate-mapping>
    <class name="beans.VerificaionCode" table="verificaion_code" catalog="myglukose" optimistic-lock="version">
        <id name="idverificaionCode" type="java.lang.Integer">
            <column name="idverificaion_code" />
            <generator class="identity" />
        </id>
        <many-to-one name="patient" class="beans.Patient" fetch="select">
            <column name="patient_idpatient" not-null="true" />
        </many-to-one>
        <property name="code" type="string">
            <column name="code" length="45" not-null="true" />
        </property>
        <property name="dateCreated" type="timestamp">
            <column name="date_created" length="19" />
        </property>
        <property name="lastUpdated" type="timestamp">
            <column name="last_updated" length="19" not-null="true" />
        </property>
    </class>
</hibernate-mapping>

Patient.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- Generated Sep 23, 2016 3:21:00 PM by Hibernate Tools 4.3.1 -->
<hibernate-mapping>
    <class name="beans.Patient" table="patient" catalog="myglukose" optimistic-lock="version">
        <id name="idpatient" type="java.lang.Integer">
            <column name="idpatient" />
            <generator class="identity" />
        </id>
        <many-to-one name="diabetesType" class="beans.DiabetesType" fetch="select">
            <column name="diabetes_type_iddiabetes_type" not-null="true" />
        </many-to-one>
        <many-to-one name="language" class="beans.Language" fetch="select">
            <column name="language_idlanguage" not-null="true" />
        </many-to-one>
        <property name="customId" type="string">
            <column name="custom_id" length="45" not-null="true" />
        </property>
        <property name="diabetesOther" type="string">
            <column name="diabetes_other" length="45" />
        </property>
        <property name="firstName" type="string">
            <column name="first_name" length="100" not-null="true" />
        </property>
        <property name="lastName" type="string">
            <column name="last_name" length="100" />
        </property>
        <property name="email" type="string">
            <column name="email" length="45" not-null="true" />
        </property>
        <property name="dob" type="date">
            <column name="dob" length="10" not-null="true" />
        </property>
        <property name="parentEmail" type="string">
            <column name="parent_email" length="45" />
        </property>
        <property name="gender" type="string">
            <column name="gender" length="45" not-null="true" />
        </property>
        <property name="diagnosedDate" type="date">
            <column name="diagnosed_date" length="10" />
        </property>
        <property name="height" type="java.lang.Double">
            <column name="height" precision="22" scale="0" />
        </property>
        <property name="weight" type="java.lang.Double">
            <column name="weight" precision="22" scale="0" />
        </property>
        <property name="heightUnit" type="string">
            <column name="height_unit" length="45" />
        </property>
        <property name="weightUnit" type="string">
            <column name="weight_unit" length="45" />
        </property>
        <property name="theme" type="string">
            <column name="theme" length="45" not-null="true" />
        </property>
        <property name="userName" type="string">
            <column name="user_name" length="45" not-null="true" />
        </property>
        <property name="password" type="string">
            <column name="password" length="45" not-null="true" />
        </property>
        <property name="dateCreated" type="timestamp">
            <column name="date_created" length="19" />
        </property>
        <property name="lastUpdated" type="timestamp">
            <column name="last_updated" length="19" not-null="true">
                <comment>Stores the basic information of the patient</comment>
            </column>
        </property>        
    </class>
</hibernate-mapping>

However when I run this code via http://localhost:8080/example_rest/rest/verificaion_code/getAllVerificationCodes I am getting the below error.

could not initialize proxy - no Session (through reference chain: java.util.ArrayList[0]->beans.VerificaionCode["patient"]->beans.Patient_$$_jvst40f_7["diabetesType"])

As you can see diabetesType is an Object (Foreign Key) in the patient's table and has nothing to do with VerificationCode. How can I fix this up?

Please note that this is a REST API. So I can't load these in a JSP like in a web app.

Update

As @Kayaman recommended, I made the updates by making null. Please check the below code. I noticed that verificaionCodes.get(i).getPatient().set...(null) makes the same error as above, so I tried below which started working fine.

VerificationCodeService.java

public List<VerificaionCode> getAllVerificationCodes() {
        Session session = verificationCodeDAOInterface.openCurrentSession();
        Transaction transaction = null;

        List<VerificaionCode> verificaionCodes = new ArrayList<VerificaionCode>();

        try {
            transaction = verificationCodeDAOInterface.openTransaction(session);
            verificaionCodes = verificationCodeDAOInterface.getAllVerificationCodes(session);

            transaction.commit();

        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            session.close();

            for(int i=0;i<verificaionCodes.size();i++)
            {
                Patient p = new Patient();

System.out.println(verificaionCodes.get(i).getPatient().getIdpatient());
                Integer idpatient = verificaionCodes.get(i).getPatient().getIdpatient();
                p.setIdpatient(idpatient);
                verificaionCodes.get(i).setPatient(p);
            }
        }

        return verificaionCodes;

    }

标签： java hibernate rest

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Hibernate: could not initialize proxy - no Session

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