hibernate - 結合テーブルの GUID を自動生成するにはどうすればよいですか?

Question

Hibernate 4.1.0.Final、JPA 2.0、および MySQL 5.5 を使用しています。次のエンティティがあります。

@GenericGenerator(name = "uuid-strategy", strategy = "uuid.hex")
@Entity
@Table(name = "cb_organization", uniqueConstraints = {@UniqueConstraint(columnNames={"organization_id"})})
public class Organization implements Serializable
{

    …

    @OneToMany(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
    @JoinTable(name = "cb_organization_address",
              joinColumns = @JoinColumn(name = "organization_id"),
              inverseJoinColumns = @JoinColumn(name = "address_id"))
    /* List of addresses associated with this organization */
    private List<Address> addresses;

結合テーブル「cb_organization_address」に注意してください。主キーは、組織エンティティの ID と同様に、GUID にしたい varchar(32) not null フィールドです。このテーブルの ID を自動生成するにはどうすればよいですか? アドレスを含む組織を保存しようとすると、例外が発生します…</p>

javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Field 'ID' doesn't have a default value
    org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1361)
    org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1289)
    org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1295)
    org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:976)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
    $Proxy47.flush(Unknown Source)
    org.mainco.subco.organization.repo.OrganizationDaoImpl.save(OrganizationDaoImpl.java:63)
    org.mainco.subco.organization.service.OrganizationServiceImpl.save(OrganizationServiceImpl.java:64)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:318)
    org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    $Proxy62.save(Unknown Source)
    org.mainco.subco.sbadmin.controllers.OrganizationController.save(OrganizationController.java:204)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
        org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:847)