How to retrieve assertions about an ontology by using OWL-API

My ontology has the following triples, where the subject is the ontology itself. Protégé visualizes them as "Annotations" in the "active ontology" tab ("Ontology header" section).

<http://myOntology/testOnto> rdf:type owl:Ontology ;
    <http://purl.org/dc/elements/1.1/creator> "Andrea"@it ;
    <http://purl.org/dc/elements/1.1/title> "test"@it ;
    rdfs:label "Andrea"@it .

How can I retrieve them by using OWL API ?

OWLOntology implements the HasAnnotations interface and these are annotations on the ontology itself. You can thus use the annotations (or annotationsAsList) method for that:

StringDocumentSource source = new StringDocumentSource("""                
                <http://myOntology/testOnto> rdf:type owl:Ontology ;
                    <http://purl.org/dc/elements/1.1/creator> "Andrea"@it ;
                    <http://purl.org/dc/elements/1.1/title> "test"@it ;
                    rdfs:label "Andrea"@it .""");
OWLOntologyManager ontologyManager; // Init ontology manager
OWLOntology loaded = ontologyManager.loadOntologyFromOntologyDocument(source);
List<OWLAnnotation> annotations = loaded.annotationsAsList();
System.out.println(annotations);