java - Hibernate exception _$$_javassist_0 cannot be cast to javassist.util.proxy.Proxy

Question

Hello I am using developnig java web application and I am getting the next exception when I am trying to fetch data using hibernate

java.lang.ClassCastException: com.digitalticket.model.UserType_$$_javassist_0 cannot be cast to javassist.util.proxy.Proxy

Here stacktrace

java.lang.ClassCastException: com.digitalticket.model.UserType_$$_javassist_0 cannot be cast to javassist.util.proxy.Proxy
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.getProxy(JavassistLazyInitializer.java:147)
    at org.hibernate.proxy.pojo.javassist.JavassistProxyFactory.getProxy(JavassistProxyFactory.java:75)
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.createProxy(AbstractEntityTuplizer.java:771)
    at org.hibernate.persister.entity.AbstractEntityPersister.createProxy(AbstractEntityPersister.java:4613)
    at org.hibernate.event.internal.DefaultLoadEventListener.createProxyIfNecessary(DefaultLoadEventListener.java:349)
    at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:270)
    at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:150)
    at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1070)
    at org.hibernate.internal.SessionImpl.internalLoad(SessionImpl.java:989)
    at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:716)
    at org.hibernate.type.EntityType.resolve(EntityType.java:502)
    at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:170)
    at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:144)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1114)
    at org.hibernate.loader.Loader.processResultSet(Loader.java:972)
    at org.hibernate.loader.Loader.doQuery(Loader.java:920)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
    at org.hibernate.loader.Loader.doList(Loader.java:2553)
    at org.hibernate.loader.Loader.doList(Loader.java:2539)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
    at org.hibernate.loader.Loader.list(Loader.java:2364)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:126)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1682)
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:380)
    at com.digitalticket.model.DAO.fetchAll(DAO.java:204)
    at com.digitalticket.controller.IndexController.handleRequestInternal(IndexController.java:22)
    at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:154)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:844)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
    at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:238)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3363)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3333)
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
    at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
    at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:57)
    at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2220)
    at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2146)
    at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2124)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1564)
    at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:254)
    at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:550)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:295)
    at weblogic.work.ExecuteThread.run(ExecuteThread.java:254)

Here my code

public T fetchAll(tClass<T> className) {

    Session s = sessionFactory.getCurrentSession();
    s.beginTransaction();

    try {

        List<T> results = (List<T>) sessionFactory.getCurrentSession()
                .createCriteria(className)
                .list();

        s.getTransaction().commit();

        return results();

    } catch (NullPointerException ex) {
        return null;
    }
    catch (RuntimeException re) {
        s.getTransaction().rollback();
        throw re;
    } finally {

    }
}

Here is my objects

public class User implements java.io.Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = -2383716625869790753L;
    private long userId;
    private UserType userType;
    private String email;
    private String password;
    private String name;
    private String surname;
    private String middlename;
    private Set<Ticket> tickets = new HashSet<Ticket>(0);
    private Set<Organization> organizations = new HashSet<Organization>(0);

    public User() {
    }

    public User(long userId, String email, String password, String name,
            String surname) {
        this.userId = userId;
        this.email = email;
        this.password = password;
        this.name = name;
        this.surname = surname;
    }

    public User(long userId, UserType userType, String email, String password,
            String name, String surname, String middlename,
            Set<Ticket> tickets, Set<Organization> organizations) {
        this.userId = userId;
        this.userType = userType;
        this.email = email;
        this.password = password;
        this.name = name;
        this.surname = surname;
        this.middlename = middlename;
        this.tickets = tickets;
        this.organizations = organizations;
    }

    public long getUserId() {
        return this.userId;
    }

    public void setUserId(long userId) {
        this.userId = userId;
    }

    public UserType getUserType() {
        return this.userType;
    }

    public void setUserType(UserType userType) {
        this.userType = userType;
    }

    public String getEmail() {
        return this.email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return this.password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return this.surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getMiddlename() {
        return this.middlename;
    }

    public void setMiddlename(String middlename) {
        this.middlename = middlename;
    }

    public Set<Ticket> getTickets() {
        return this.tickets;
    }

    public void setTickets(Set<Ticket> tickets) {
        this.tickets = tickets;
    }

    public Set<Organization> getOrganizations() {
        return this.organizations;
    }

    public void setOrganizations(Set<Organization> organizations) {
        this.organizations = organizations;
    }

}

public class UserType implements java.io.Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = -206438165274679246L;
    private long userTypeCode;
    private String userTypeName;
    private Set<User> users = new HashSet<User>(0);

    public UserType() {
    }

    public UserType(long userTypeCode, String userTypeName) {
        this.userTypeCode = userTypeCode;
        this.userTypeName = userTypeName;
    }

    public UserType(long userTypeCode, String userTypeName, Set<User> users) {
        this.userTypeCode = userTypeCode;
        this.userTypeName = userTypeName;
        this.users = users;
    }

    public long getUserTypeCode() {
        return this.userTypeCode;
    }

    public void setUserTypeCode(long userTypeCode) {
        this.userTypeCode = userTypeCode;
    }

    public String getUserTypeName() {
        return this.userTypeName;
    }

    public void setUserTypeName(String userTypeName) {
        this.userTypeName = userTypeName;
    }

    public Set<User> getUsers() {
        return this.users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }

}

here is mappings

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                                   "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- Generated Mar 16, 2014 10:31:53 AM by Hibernate Tools 4.0.0 -->
<hibernate-mapping>
    <class name="com.digitalticket.model.User" table="&quot;USER&quot;">
        <id name="userId" type="long">
            <column name="USER_ID" precision="10" scale="0" />
            <generator class="assigned" />
        </id>
        <many-to-one class="com.digitalticket.model.UserType"
            fetch="select" name="userType">
            <column name="USER_TYPE" precision="10" scale="0" />
        </many-to-one>
        <property generated="never" lazy="false" name="email" type="string">
            <column length="20" name="EMAIL" not-null="true" unique="true" />
        </property>
        <property generated="never" lazy="false" name="password"
            type="string">
            <column length="32" name="PASSWORD" not-null="true" />
        </property>
        <property generated="never" lazy="false" name="name" type="string">
            <column length="64" name="NAME" not-null="true" />
        </property>
        <property generated="never" lazy="false" name="surname" type="string">
            <column length="64" name="SURNAME" not-null="true" />
        </property>
        <property generated="never" lazy="false" name="middlename"
            type="string">
            <column length="64" name="MIDDLENAME" />
        </property>
        <set fetch="select" inverse="true" lazy="true" name="tickets"
            sort="unsorted" table="TICKET">
            <key>
                <column 

Answer 1

I use with hibernate 4.3.5.Final and have similar problem with javassist, the problem is that javassist is missing, and you can get the latest from the Maven repositorty.

<dependency>
    <groupId>org.javassist</groupId>
    <artifactId>javassist</artifactId>
    <version>3.18.1-GA</version> 
</dependency>

In later editions it is fixed again

With this all works in my case,