My form backing object has a Map field.
When I create new backing object by "new" operator, form is rendered correct:

form.jsp
--- cut ---
<spring:bind path="myForm.myObject.mapField[${key}].stringField">
<input type="text" name="<c:out value="${status.expression}"/>" value="<c:out value="${status.value}"/>"/>
</spring:bind>
--- end cut ---

but, when I use this form for edit this object retrieved from DB by Hibernate, I has error:
org.springframework.beans.NullValueInNestedPathExc eption: Invalid property 'myObject.mapField[12]' of bean class [tld.domain.myObject]: Value of nested property 'myObject.mapField[12]' is null
org.springframework.beans.BeanWrapperImpl.getNeste dBeanWrapper(BeanWrapperImpl.java:482) org.springframework.beans.BeanWrapperImpl.getBeanW rapperForPropertyPath(BeanWrapperImpl.java:399) org.springframework.beans.BeanWrapperImpl.getBeanW rapperForPropertyPath(BeanWrapperImpl.java:400) org.springframework.beans.BeanWrapperImpl.getPrope rtyValue(BeanWrapperImpl.java:537) org.springframework.validation.BindException.getFi eldValue(BindException.java:265) org.springframework.web.servlet.support.BindStatus .(BindStatus.java:115) org.springframework.web.servlet.tags.BindStatus.(B indStatus.java:38) org.springframework.web.servlet.tags.BindTag.doSta rtTagInternal(BindTag.java:103) org.springframework.web.servlet.tags.RequestContex tAwareTag.doStartTag(RequestContextAwareTag.java:7 0)

at the same time expression <c:out value="${myForm.myObject.mapField[key].stringField}"/> display value of stringField correctly

I did debug application and find the following conclusion: this error throws becaouse map retrived by hibernate from DB has type net.sf.hibernate.collection.Map, but class org.springframework.beans.BeanWrapperImpl on method getPropertyValue has the folowing logic:
--- cut ---
....
import java.util.Map
....
else if (value instanceof Map) {
Map map = (Map) value;
return map.get(key);
}
-- end cut ---

i.e. problem exists because myObject.mapField has type net.sf.hibernate.collection.Map instead java.util.Map after retrieving by Hibernate,
net.sf.hibernate.collection.Map ia a persistent wrapper for a java.util.Map.

I think this problem exists for eny collection mapped to DB with Hibernate.

Any suggestions about elegant solving of this problem ?