Hi
I recently faced an issue using Hibernate with Tomcat.
Initially i had two tables JOB and Jobfeed. Which had one to many relationship.
JobFeed had FK JOB_ID from JOB table.
So when said give me all the feeds for Job id 8 it wokrd perfectly fine for me. ( It had 120K records)
But then I had to restructure the table and then had to make many to many relation with link table.

so now there are 3 tables
1. JOB with job_ID and other info
2. FEEDS with FEED_ID and other info
3. link table JOB_FEED which has JOB_ID and FEED_ID

now the mapping in job.hbm looks as follows

<set name="feeds" table="JOB_FEED" cascade="none">
<key>
<column name="JOB_ID" precision="22" scale="0" not-null="true" />
</key>
<many-to-many class="Feed" column="FEED_ID" />
</set>

and mapping in FEEDS table is

<set name="jobs" table="JOB_FEED" inverse="true">
<key>
<column name="FEED_ID" precision="22" scale="0" not-null="true" />
</key>
<many-to-many class="Job" column="JOB_ID" />
</set>

And when I try to get job for all feeds I get OutOfMemory in same tomcat server with same amount of data.