XmlSeeAlso enhancements

@glassfishrobot is already working on this.

Since Sep 21, 2018.

I have three enhancement suggestions for @XmlSeeAlso.

1\. Allow @XmlSeeAlso to be applied to a package via package-info.java. This
will help greatly in decoupling base classes from their subclasses.

2\. Check for @XmlSeeAlso on XmlAdapter implementation classes that have been
specified via @XmlJavaTypeAdapter. This will also help greatly in decoupling
base classes from their subclasses.

3\. Allow for specifying an array of package name strings via @XmlSeeAlso. This
would work in a similar way as creating a JAXBContext with a list of package
names in that the package(s) would be scanned for classes. This one would be a
tremendous help in adding runtime flexibility to JAXB when used with JAXWS –
extension subclasses could be loaded at runtime that are not available at
compile time.

public @interface XmlSeeAlso {
Class[] value();
String[] packages();
}
#### Environment
Operating System: All
Platform: All
#### Affected Versions
[2.2]