question: private Element resolveSchema ( XSDDescription desc , boolean mustResolve , Element referElement , boolean usePairs ) { XMLInputSource schemaSource = null ; try { Hashtable pairs = usePairs ? fLocationPairs : EMPTY_TABLE ; schemaSource = XMLSchemaLoader . resolveDocument ( desc , pairs , fEntityResolver ) ; } catch ( IOException ex ) { if ( mustResolve ) { reportSchemaError ( "schema_reference.4" , new Object [ ] { desc . getLocationHints ( ) [ 0 ] } , referElement ) ; } else { reportSchemaWarning ( "schema_reference.4" , new Object [ ] { desc . getLocationHints ( ) [ 0 ] } , referElement ) ; } } if ( schemaSource instanceof DOMInputSource ) { return getSchemaDocument ( desc . getTargetNamespace ( ) , ( DOMInputSource ) schemaSource , mustResolve , desc . getContextType ( ) , referElement ) ; } else if ( schemaSource instanceof SAXInputSource ) { return getSchemaDocument ( desc . getTargetNamespace ( ) , ( SAXInputSource ) schemaSource , mustResolve , desc . getContextType ( ) , referElement ) ; } else if ( schemaSource instanceof StAXInputSource ) { return getSchemaDocument ( desc . getTargetNamespace ( ) , ( StAXInputSource ) schemaSource , mustResolve , desc . getContextType ( ) , referElement ) ; } else if ( schemaSource instanceof XSInputSource ) { return getSchemaDocument ( ( XSInputSource ) schemaSource , desc ) ; } return getSchemaDocument ( desc . getTargetNamespace ( ) , schemaSource , mustResolve , desc . getContextType ( ) , referElement ) ; }
target:  resolveSchema method is responsible for resolving location of the schema (using XMLEntityResolver), and if it was succefully resolved getting the schema Document.