According to the spec, source should not be null and should be a
validated type, and as the spec says:
"the MBean Server will rewrite the source to be the ObjectName under
which that MBean is registered." in case the source is a RelationService
object
this means that the MBean Server might get a NPE when treating the
source, or a user will get NPE, so it is definitively a bug to set the
source null.
I am OK if you prefer to fix JCP break at first, then to fix non-null
issue in setSource and readObject, but I am afraid that fixing non-null
issue would break JCK again, not sure.
Shanliang
Dmitry Samersoff wrote:
Shanlinag,
The main goal of this fix - is preserve a compatibility in cross-version
environment upon request of JCK team.
i.e. it's possible to create an RelationNotification instance using
early version of JDK, set sourceObj to null, serialize it and give this
serialized object to latest update with the validation.
So we can't refuse such serialized stream and as soon as null
sourceObject can't cause any harm I decided to relax a
valiadation during *desereliazion*.
Constructor is not affected - it still throws IAE if sourceObj is null,
as it happens today and described in javadoc.
I'm not sure whether it make sense to change setSource as well to
prevent setting sourceObject to null in the future - probably yes, but
compatibility impact of these changes have to be evaluated separately
and it's clearly out of scope of this CR.
-Dmitry
On 2013-07-03 11:00, shanliang wrote:
After reading again the constructor Javadoc:
"sourceObj - source object, sending the notification. This is either an
ObjectName or a RelationService object. In the latter case it must be
the MBean emitting the notification; the MBean Server will rewrite the
source to be the ObjectName under which that MBean is registered."
In this case, should we override instead the method "setSource" to
refuse a null value and do the necessary check? like
setSource(Object source) {
if (!(sourceObj instanceof RelationService) &&
!(sourceObj instanceof ObjectName))) {
throw new IllegalArgumentException();
}
}
Shanliang
shanliang wrote:
The constructor Javadoc says: "Throws IllegalArgumentException if no
source object", we have to modify the spec if the implementation is
changed.
Shanliang
Dmitry Samersoff wrote:
Hi Everybody,
*problem*
Despite the fact, that validation in constructor of RelationNotification
prohibit creation of the class instance with null sourceObj its possible
to set it to null later by public setSource() method. So we should relax
validation rules to preserve serialization behavior compatibility.
*webrev*
http://cr.openjdk.java.net/~dsamersoff/8011038/webrev.01/
*testing*
JCK, no separate regression tests required.
