已经郁闷两天了 hibernate 报Duplicate collection role mapping异常

已经郁闷两天了 hibernate 报Duplicate collection role mapping错误
自己做的一个hibernate的小程序，两个类TLendLog 和TBookMaster 还有它们的配置文件。
然后自己做了一个测试类 test1,里面只有一句话。 程序很简单，但是报 Duplicate collection role mapping错误

弄得我已经郁闷两天了，麻烦高手看一下。


package book.bean;
public class TLendLog implements java.io.Serializable {

  private Long userMaster;
  private Long bookMaster;
private String updatePerson;

  public String getUpdatePerson() {
  return updatePerson;
  }

  public void setUpdatePerson(String updatePerson) {
  this.updatePerson = updatePerson;
  }


  public Long getUserMaster() {
  return userMaster;
  }


  public void setUserMaster(Long userMaster) {
  this.userMaster = userMaster;
  }


  public Long getBookMaster() {
  return bookMaster;
  }

  public void setBookMaster(Long bookMaster) {
  this.bookMaster = bookMaster;
  }

}



package book.bean;
import java.util.*;
public class TBookMaster implements java.io.Serializable {

private Long bookId;
private String bookTitle;
private Set logs = new HashSet(0);

public Long getBookId() {
return this.bookId;
}

public void setBookId(Long bookId) {
this.bookId = bookId;
}

public String getBookTitle() {
return this.bookTitle;
}

public void setBookTitle(String bookTitle) {
this.bookTitle = bookTitle;
}

  public Set getLogs() {
  return logs;
  }

  public void setLogs(Set logs) {
  this.logs = logs;
  }

}


<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
  Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
  <class name="book.bean.TBookMaster" table="T_BOOK_MASTER" schema="SCOTT">
  <id name="bookId" type="java.lang.Long">
  <column name="BOOK_ID" precision="9" scale="0" />
  <generator class="assigned" />
  </id>
  <property name="bookTitle" type="java.lang.String">
  <column name="BOOK_TITLE" length="30" not-null="true" />
  </property>
  <set name="logs" inverse="true">
  <key>
  <column name="BOOK_ID" not-null="true" />
  </key>
  <one-to-many class="book.bean.TLengLog" />
  </set> 
  </class>
</hibernate-mapping>


<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
  Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
  <class name="book.bean.TLendLog" table="T_LEND_LOG" schema="SCOTT">
  <id name="userMaster" type="java.lang.Long">
  <column name="USER_ID" precision="9" scale="0" />