The new XML Catalog API, delivered with Java 9, follows the OASIS XML Catalogs standard, v1.1. Here are the feature and capability highlights:

• Implements EntityResolver.
• Implements URIResolver.
• Creation of XML Catalogs is possible via the CatalogManager.
• CatalogManager will be used to create CatalogResolvers.
• OASIS open catalog file semantics will be followed:
• Maps an external identifier to a URI reference
• Maps a URI reference to another URI reference

• CatalogResolvers will implement the JAXP EntityResolver interface.
• CatalogResolvers will implement the JAXP URIResolver interface.
• The SAX XMLFilter will be supported by the resolver.

Since the new XML Catalog API is public, the pre-Java 9 internal catalog resolver has been removed, as it is no longer necessary.