<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="userprofile.layer.domain" auto-import="true" default-lazy="false" default-cascade="persist" default-access="property">
   
   <!-- User Table Mapping -->

   <class name="User" table="USER">
      <id name="userID" column="USER_ID">
           <generator class="assigned"/>
        </id>      

      <property name="firstName" column="FIRST_NAME"/>
      <property name="middleInitial" column="MIDDLE_INITIAL"/>      
      <property name="lastName" column="LAST_NAME"/>
      
      <one-to-one name="userAddress" class="UserAddress"/>
      <one-to-one name="userContInfo" class="UserContInfo"/>

   </class>

   <!-- User Address Table Mapping -->   

   <class name="UserAddress" table="USER_ADDRESS">      
      <id name="userID" column="USER_ID">
         <generator class="foreign">
            <param name="property">userObj</param>
         </generator>
      </id>      
      
      <one-to-one name="userObj" class="User" constrained="true"/>
         
      
      
      <property name="address1" column="ADDRESS_1"/>
      <property name="address2" column="ADDRESS_2"/>
      <property name="cityName" column="CITY_NAME"/>
      <property name="state" column="STATE"/>
      <property name="country" column="COUNTRY"/>
      <property name="zipCode" column="ZIP_CODE"/>         
   </class>

   <!-- User Contact Info Table Mapping -->   

   <class name="UserContInfo" table="USER_CONT_INFO">      
      <id name="userID" column="USER_ID">
         <generator class="foreign">
            <param name="property">userObj</param>
         </generator>
      </id>      
      
      <one-to-one name="userObj" class="User" constrained="true"/>
         
      <property name="emailID" column="EMAIL_ID"/>
      <property name="cellPhone" column="CELL_PHONE"/>
      <property name="homePhone" column="HOME_PHONE"/>
   </class>
</hibernate-mapping>

org.springframework.orm.hibernate3.HibernateSystemException: attempted to assign id from null one-to-one property: userObj

public class User {
   private int userID;
   
   private String firstName;
   private String middleInitial;
   private String lastName;
   private UserAddress userAddress = new UserAddress();
   private UserContInfo userContInfo = new UserContInfo();
   
   public User(){      
   }
   
   /**
    * @return Returns the firstName.
    */
   public String getFirstName() {
      return firstName;
   }
   /**
    * @param firstName The firstName to set.
    */
   public void setFirstName(String firstName) {
      this.firstName = firstName;
   }
   /**
    * @return Returns the lastName.
    */
   public String getLastName() {
      return lastName;
   }
   /**
    * @param lastName The lastName to set.
    */
   public void setLastName(String lastName) {
      this.lastName = lastName;
   }
   /**
    * @return Returns the middleInitial.
    */
   public String getMiddleInitial() {
      return middleInitial;
   }
   /**
    * @param middleInitial The middleInitial to set.
    */
   public void setMiddleInitial(String middleInitial) {
      this.middleInitial = middleInitial;
   }
   /**
    * @return Returns the userID.
    */
   public int getUserID() {
      return userID;
   }
   /**
    * @param userID The userID to set.
    */
   public void setUserID(int userID) {
      this.userID = userID;
   }   
   
   /**
    * @return Returns the userAddress.
    */
   public UserAddress getUserAddress() {
      return userAddress;
   }
   /**
    * @param userAddress The userAddress to set.
    */
   public void setUserAddress(UserAddress userAddress) {
      this.userAddress = userAddress;
   }

   /**
    * @return the userContInfo
    */
   public UserContInfo getUserContInfo() {
      return userContInfo;
   }

   /**
    * @param userContInfo the userContInfo to set
    */
   public void setUserContInfo(UserContInfo userContInfo) {
      this.userContInfo = userContInfo;
   }
   
   
}

public class UserAddress {
   private int userID;   
   private String address1;
   private String address2;
   private String cityName;
   private String state;
   private String country;
   private String zipCode;
   private User userObj;
   //private UserAddressCompositeKey userAddressCompKey;   
   
   public UserAddress(){      
   }

   /**
    * @return Returns the addressLine1.
    */
   public String getAddress1() {
      return address1;
   }
   /**
    * @param addressLine1 The addressLine1 to set.
    */
   public void setAddress1(String address1) {
      this.address1 = address1;
   }
   /**
    * @return Returns the addressLine2.
    */
   public String getAddress2() {
      return address2;
   }
   /**
    * @param addressLine2 The addressLine2 to set.
    */
   public void setAddress2(String address2) {
      this.address2 = address2;
   }
   /**
    * @return Returns the cityName.
    */
   public String getCityName() {
      return cityName;
   }
   /**
    * @param cityName The cityName to set.
    */
   public void setCityName(String cityName) {
      this.cityName = cityName;
   }

   /**
    * @return Returns the country
    */
   public String getCountry() {
      return country;
   }
   /**
    * @param country The country to set.
    */
   public void setCountry(String country) {
      this.country = country;
   }
   /**
    * @return Returns the stateProvince.
    */
   public String getState() {
      return state;
   }
   /**
    * @param State The State to set.
    */
   public void setState(String state) {
      this.state = state;
   }
   /**
    * @return Returns the userID.
    */
   public int getUserID() {
      return userID;
   }
   /**
    * @param userID The userID to set.
    */
   public void setUserID(int userID) {
      this.userID = userID;
   }
   /**
    * @return Returns the zipCode.
    */
   public String getZipCode() {
      return zipCode;
   }
   /**
    * @param zipCode The zipCode to set.
    */
   public void setZipCode(String zipCode) {
      this.zipCode = zipCode;
   }

   /**
    * @return the userObj
    */
   public User getUserObj() {
      return userObj;
   }

   /**
    * @param userObj the userObj to set
    */
   public void setUserObj(User userObj) {
      this.userObj = userObj;
   }

   
      
}