Creation d'une seule instance de validator pour l'objet

DCToSeda21Converter

src/main/java/fr/cines/pac/converter/DCToSeda21Converter.java

@@ -247,7 +247,9 @@ public class DCToSeda21Converter extends AbstractArchiveConverter {
 
 	static {
 		ValidatorFactory vf = new ValidatorFactory();
-		validator = vf.createValidator();
+		if (validator == null) {
+		    validator = vf.createValidator();
+		} 
 	}
 	public static List<String> formatVideoList = Arrays.asList("AAC", "MPEG-4", "AIFF", "FLAC", "MKV", "OGG", "WAV");
 	private Properties properties;