ClassCastException with ClassLoader issues

Question

I'm using JBoss 3.2.3, with Kodo 3.1.0
After doing a hot deploy in JBoss, ClassCastExceptions start occuring.
String filter = "reference==param1";
Extent extent = pm.getExtent(Customer.class, false);
KodoQuery query = (KodoQuery) pm.newQuery(extent, filter);
Collection col = null;
try {
query.declareParameters("String param1");
col = (Collection) query.execute("x34c");
if (col.isEmpty())
return null;
Customer cust = (Customer) col.iterator().next();
finally {
if (query != null)
query.close(col);
At the line: Customer cust = (Customer) col.iterator().next();
a ClassCastException is thrown. The class loader for Customer.class point
to the deployed ear file, whilst the loader for
col.iterator().next().getClass() points to null.
Now, what is even more interesting is if I amend the above code slightly:
Extent extent = pm.getExtent(Customer.class, false);
KodoQuery query = (KodoQuery) pm.newQuery(extent);
Collection col = null;
try {
col = (Collection) query.execute();
if (col.isEmpty())
return null;
Customer cust = (Customer) col.iterator().next();
finally {
if (query != null)
query.close(col);
With the above, everything works fine. The only difference is that one
uses a filter to retrieve a particular object from the datastore, and the
other retrieves all objects from the datastore. I don't understand why it
throws a ClassCastException in one instance and not the other. Note that
this only happens after a hot deploy.
This problem only surfaced recently after I added a few more classes to be
persistent capable. After adding a further two classes, the
ClassCastException moved to another class.
Can anyone explain this?
Cheers

Answer 1

A N-
Did you make absolutely sure that you enhanced all of the new classes
and deployed them to correctly, and that you have clobbered any caches
JBoss may have to any of the old .ear files?
It might be the case that when you obtain the first in the list of all
the Customer instances, it doesn't have a relation to one of the new
classes, or its concrete instance is not one of the new classes, as
opposed to when you execute the filter.
If this doesn't help, can you provide us with some more information? At
a minimum, a complete stack trace is usually a prerequisite for being
able to diagnose problems like this.
In article <[email protected]>, A N wrote:
>
I'm using JBoss 3.2.3, with Kodo 3.1.0
After doing a hot deploy in JBoss, ClassCastExceptions start occuring.
String filter = "reference==param1";
Extent extent = pm.getExtent(Customer.class, false);
KodoQuery query = (KodoQuery) pm.newQuery(extent, filter);
Collection col = null;
try {
query.declareParameters("String param1");
col = (Collection) query.execute("x34c");
if (col.isEmpty())
return null;
Customer cust = (Customer) col.iterator().next();
finally {
if (query != null)
query.close(col);
At the line: Customer cust = (Customer) col.iterator().next();
a ClassCastException is thrown. The class loader for Customer.class point
to the deployed ear file, whilst the loader for
col.iterator().next().getClass() points to null.
Now, what is even more interesting is if I amend the above code slightly:
Extent extent = pm.getExtent(Customer.class, false);
KodoQuery query = (KodoQuery) pm.newQuery(extent);
Collection col = null;
try {
col = (Collection) query.execute();
if (col.isEmpty())
return null;
Customer cust = (Customer) col.iterator().next();
finally {
if (query != null)
query.close(col);
With the above, everything works fine. The only difference is that one
uses a filter to retrieve a particular object from the datastore, and the
other retrieves all objects from the datastore. I don't understand why it
throws a ClassCastException in one instance and not the other. Note that
this only happens after a hot deploy.
This problem only surfaced recently after I added a few more classes to be
persistent capable. After adding a further two classes, the
ClassCastException moved to another class.
Can anyone explain this?
Cheers
Marc Prud'hommeaux [email protected]
SolarMetric Inc. http://www.solarmetric.com