Xerces has an XML Catalog implementation in the class:

org.apache.xerces.util.XMLCatalogResolver

You just create the class and set the list of catalog files:

String catalogURI = "file:"+(new File(catalogFile)).getAbsolutePath();
String [] catalogs = { catalogURI };

// Create catalog resolver and set a catalog list.
XMLCatalogResolver resolver = new XMLCatalogResolver();
resolver.setPreferPublic(true);
resolver.setCatalogList(catalogs);

Then set the appropriate property:

// Set the resolver on the parser.
xmlReader.setProperty(
   "http://apache.org/xml/properties/internal/entity-resolver", 
   resolver
);