Hibernate version:
3.2.4

Mapping documents:
<class table="LPN" name="com.xxx.lpn.LPN" dynamic-insert="true" dynamic-update="true">

<id type="java.lang.Long" column="LPN_ID" access="property" name="lpnId">
<generator class="sequence">
<param name="sequence">LPN_ID_SEQ</param>
</generator>
</id>
<version type="java.lang.Long" column="VERSION" access="field" name="hibernateVersion"/>

......
</class>


Here is the flow:
<b>Scenario 1 : </b>
1. Initiate transaction using TransactionTemplate/or Spring Proxy or EJB.
2. Load the LPN object
3. Evict the object from session
4. Update the LPN object with different values.

In above case the dynamic udpate doesn't work and hibernate sql shows that it's updating all the columns. If we skip the #3 then dynamic update is working. Does any one know the reason behind it?

To generate dynamic update statement (when you use dynamic-update=true), Hibernate need to know what properties has changed. Hibernate do this by comparing the object state with the state in persistence context (that is associated with session). so if you evict the object from session (means from the persistence context), hibernate can't find out what properties have change and then by default it will have all the properties in update statement.

please modify as mention below and try. I hope it will help you to generate the dynamic update statement.