#fixed code
                                private Object createRelationshipEntity(Edge edge, Object startEntity, Object endEntity) {

        ClassInfo relationClassInfo = getRelationshipEntity(edge);
        if (relationClassInfo == null) {
            throw new MappingException("Could not find a class to map for relation " + edge);
        }

        Map<String, Object> allProps = new HashMap<>(toMap(edge.getPropertyList()));
        getCompositeProperties(edge.getPropertyList(), relationClassInfo).forEach( (k, v) -> {
            allProps.put(k.getName(), v);
        });
        // also add start and end node as valid constructor values
        allProps.put(relationClassInfo.getStartNodeReader().getName(), startEntity);
        allProps.put(relationClassInfo.getEndNodeReader().getName(), endEntity);

        // create and hydrate the new RE
        Object relationshipEntity = entityFactory
            .newObject(relationClassInfo.getUnderlyingClass(), allProps);
        EntityUtils.setIdentity(relationshipEntity, edge.getId(), metadata);

        // REs also have properties
        setProperties(edge.getPropertyList(), relationshipEntity);

        // register it in the mapping context
        mappingContext.addRelationshipEntity(relationshipEntity, edge.getId());

        // set the start and end entities
        ClassInfo relEntityInfo = metadata.classInfo(relationshipEntity);

        FieldInfo startNodeWriter = relEntityInfo.getStartNodeReader();
        if (startNodeWriter != null) {
            startNodeWriter.write(relationshipEntity, startEntity);
        } else {
            throw new RuntimeException(
                "Cannot find a writer for the StartNode of relational entity " + relEntityInfo.name());
        }

        FieldInfo endNodeWriter = relEntityInfo.getEndNodeReader();
        if (endNodeWriter != null) {
            endNodeWriter.write(relationshipEntity, endEntity);
        } else {
            throw new RuntimeException(
                "Cannot find a writer for the EndNode of relational entity " + relEntityInfo.name());
        }

        return relationshipEntity;
    }
#vulnerable code 
                                private Object createRelationshipEntity(Edge edge, Object startEntity, Object endEntity) {

        // create and hydrate the new RE
        Object relationshipEntity = entityFactory.newObject(getRelationshipEntity(edge));
        EntityUtils.setIdentity(relationshipEntity, edge.getId(), metadata);

        // REs also have properties
        setProperties(edge.getPropertyList(), relationshipEntity);

        // register it in the mapping context
        mappingContext.addRelationshipEntity(relationshipEntity, edge.getId());

        // set the start and end entities
        ClassInfo relEntityInfo = metadata.classInfo(relationshipEntity);

        FieldInfo startNodeWriter = relEntityInfo.getStartNodeReader();
        if (startNodeWriter != null) {
            startNodeWriter.write(relationshipEntity, startEntity);
        } else {
            throw new RuntimeException(
                "Cannot find a writer for the StartNode of relational entity " + relEntityInfo.name());
        }

        FieldInfo endNodeWriter = relEntityInfo.getEndNodeReader();
        if (endNodeWriter != null) {
            endNodeWriter.write(relationshipEntity, endEntity);
        } else {
            throw new RuntimeException(
                "Cannot find a writer for the EndNode of relational entity " + relEntityInfo.name());
        }

        return relationshipEntity;
    } 
                            #location 16 
                            #vulnerability type NULL_DEREFERENCE