With the introduction of the new public Catalog API [1][2], the old JDK internal API in package com.sun.org.apache.xml.internal.resolver and com.sun.org.apache.xerces.internal.util.XMLCatalogResolver shall be deprecated. This internal API was added to the JDK without a public API. With JDK 9, this internal API is encapsulated (not exported), users of this API shall consider migrating to the public API. The deprecation therefore is a further notice and also serves as an option to remove it in a future release.

[1] http://openjdk.java.net/jeps/268
[2] http://download.java.net/java/jdk9/docs/api/javax/xml/catalog/package-summary.html