output: #fixed code
                               private Object createRelationshipEntity(Edge edge, Object startEntity, Object endEntity) {
  
  		// create and hydrate the new RE
  		Object relationshipEntity = entityFactory.newObject(getRelationshipEntity(edge));
  		setIdentity(relationshipEntity, edge.getId());
  
  		// REs also have properties
  		setProperties(edge, relationshipEntity);
  
  		// register it in the mapping context
  		mappingContext.registerRelationshipEntity(relationshipEntity, edge.getId());
  
  		// set the start and end entities
  		ClassInfo relEntityInfo = metadata.classInfo(relationshipEntity);
  
  		RelationalWriter startNodeWriter = EntityAccessManager.getRelationalEntityWriter(relEntityInfo, StartNode.class);
  		if (startNodeWriter != null) {
  			startNodeWriter.write(relationshipEntity, startEntity);
  		} else {
  			throw new RuntimeException("Cannot find a writer for the StartNode of relational entity " + relEntityInfo.name());
  		}
  
  		RelationalWriter endNodeWriter = EntityAccessManager.getRelationalEntityWriter(relEntityInfo, EndNode.class);
  		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;
  	}
input: #vulnerable code 
                               private Object createRelationshipEntity(Edge edge, Object startEntity, Object endEntity) {
  
  		// create and hydrate the new RE
  		Object relationshipEntity = entityFactory.newObject(getRelationshipEntity(edge));
  		setIdentity(relationshipEntity, edge.getId());
  
  		// REs also have properties
  		setProperties(edge, relationshipEntity);
  
  		// register it in the mapping context
  		mappingContext.registerRelationshipEntity(relationshipEntity, edge.getId());
  
  		// set the start and end entities
  		ClassInfo relEntityInfo = metadata.classInfo(relationshipEntity);
  
  		RelationalWriter startNodeWriter = entityAccessStrategy.getRelationalEntityWriter(relEntityInfo, StartNode.class);
  		if (startNodeWriter != null) {
  			startNodeWriter.write(relationshipEntity, startEntity);
  		} else {
  			throw new RuntimeException("Cannot find a writer for the StartNode of relational entity " + relEntityInfo.name());
  		}
  
  		RelationalWriter endNodeWriter = entityAccessStrategy.getRelationalEntityWriter(relEntityInfo, EndNode.class);
  		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 20 
                              #vulnerability type NULL_DEREFERENCE