It would be great if the ScrptConverter._serialize() would output the serialization stack with the error to help identify why an object is not serializing. I was running into issues today trying to track down why an object would not serialize and I ended up having to download the source code and do an interactive debugging session to track what was happening.

Even just modifying the throw new ConverterException("can't serialize Object of type [ " + Caster.toClassName(object) + " ]"); line with something like this would be tremendously helpful:

This would print out the results of the serialization string, which should point where in the CF code the problem occurred. A better solution would be to end up generating an error which contained the class name and the specific path to the object, for example something that looked like:

cannott serialize ‘customer.variables.addresss.this.logger.sessioni.requestContext.variables.Coldbox.variables.foo’ as [ org.apache.tomcat.util.log.SystemLogHandler ] object is not serializable