Hibernate insert 错误

大家好！我使用了标准的SSH结构，在插入一个表时总是报错。程序如下：1. Admin.java (POJO)
public class Admin {
private String adminCn;
private String adminName;
public Admin(String adminCn, String adminName) {
super();
this.adminCn = adminCn;
this.adminName = adminName;
} public Admin() {
} public String getAdminCn() {
return adminCn;
} public void setAdminCn(String adminCn) {
this.adminCn = adminCn;
} public String getAdminName() {
return adminName;
} public void setAdminName(String adminName) {
this.adminName = adminName;
}}
2. hbm.xml
<?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>
    <class name="model.Admin" table="admin" schema="LLS">
        <id name="adminCn" type="string">
            <column name="Admin_Cn" length="100"/>
        </id>
        
        <property name="adminName" type="string">
            <column name="Admin_Name" length="200" />
        </property>
        
    </class>
</hibernate-mapping>3.通过service到AdminDaoImpl.java
public void insert(Admin admin){
  insert(admin);
}其中insert为继承的
public <T> Serializable insert(T entity) throws RuntimeException {
try {
return this.getHibernateTemplate().save(entity);
} catch (RuntimeException re) {
throw re;
}
}
程序运行到insert时，抛错：2009-12-11 16:26:53 org.apache.struts.actions.DispatchAction dispatchMethod
严重: Dispatch[/administration/adminAction] to method 'createAdmin' returned an exception
java.lang.reflect.InvocationTargetException
........Caused by: java.lang.StackOverflowError
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
at com.infineon.lls.daoimpl.AdminDaoImpl.insert(AdminDaoImpl.java:15)
这个错误大概有上百条。不知道是什么原因，还请大家帮忙。