I am getting following error messages and I can use join
Duplicate collection role mapping com.co803.data.Member.books
Could not read mappings from resource: com/data/Member.hbm.xml
Association references unmapped class: com.data.Book

Any idea if you please...

This is my member mapping
<hibernate-mapping package="com.data">
<class name="Member" table="member">
<id name="no" type="java.lang.Integer">
<column name="no" />
<generator class="increment"></generator>
</id>
<set name="books" table="Book" inverse="false" >
<key>
<column name="id"></column>
</key>
<one-to-many class="Book" />
</set>
<property name="name" type="java.lang.String">
<column name="name" length="100" not-null="true" />
</property>
.
.
.
.

This is my member mapping
<hibernate-mapping package="com.data">
<class name="Book" table="book">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="increment"></generator>
</id>
<many-to-one name="member" column="no" not-null="true" />
<property name="name" type="java.lang.String">
<column name="name" not-null="true" />
</property>
.
.
.
.
This is my hibernate.cfg.xml
<mapping resource="com/data/Member.hbm.xml" />
<mapping resource="com/data/Book.hbm.xml" />

Don't map the book collection key to the ID of the book table. It should be a foreign key refering back to member, so call it member_id, say.

it was mapping problem. I solved it...