SPARQL DEFINE output:format '_JAVA_' CONSTRUCT { ?s ?p ?o } WHERE { ?s ?p ?o . FILTER (?s = iri(?::0)) } LIMIT 1
In order to work correctly, the query should be modified to:
SPARQL DEFINE output:format '_JAVA_' CONSTRUCT { `iri(?::0)` ?p ?o } WHERE { `iri(?::0)` ?p ?o } LIMIT 1
Equivalent variant of the query is also:
SPARQL DEFINE output:format '_JAVA_' CONSTRUCT { ?s ?p ?o } WHERE { ?s ?p ?o . FILTER (?s = iri(?::0)) } LIMIT 1