diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index fb5b53bff..48bed0f8c 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -439,7 +439,7 @@ jpgf_collect_morpho(PgfMorphoCallback* self,
 	                                gu2j_string(env,lemma),
 	                                gu2j_string(env,analysis),
 	                                (double) prob);
-	(*env)->CallObjectMethod(env, callback->analyses, callback->addId, jan);
+	(*env)->CallBooleanMethod(env, callback->analyses, callback->addId, jan);
 	(*env)->DeleteLocalRef(env, jan);
 }