The Catalog API defines a standard solution for resolving external resources referenced by XML documents. It is fully supported by the XML Processors allowing application developers to configure a catalog through an XML processor or system property or the configuration file to take advantage of the feature.

The XML Catalog API defines the following interfaces:

• Catalog -- The Catalog interface represents an entity catalog as defined by the Catalog standard. A Catalog object is immutable. Once created, it can be used to find matches in a system, public or uri entry. A custom resolver implementation may find it useful for locating local resources through a catalog.
• CatalogFeatures -- The CatalogFeatures class holds all of the features and properties the Catalog API supports, including javax.xml.catalog.files, javax.xml.catalog.defer, javax.xml.catalog.prefer, and javax.xml.catalog.resolve.
• CatalogManager -- The CatalogManager class manages the creation of XML catalogs and catalog resolvers.
• CatalogResolver -- The CatalogResolver class is a Catalog resolver that implements EntityResolver, XMLResolver, LSResourceResolver, and URIResolver, and resolves external references using catalogs.

Unless otherwise noted, passing a null argument to a constructor or method in any class or interface in this package will cause a NullPointerException to be thrown.