org.hibernate.loader.MultipleBagFetchException: cannot simultaneously fetch multiple bags

Question

Following is my code Here I am using multiple lists to fetch data from database. On fetching data from hql query it is showing exception.

Pojo Class

Answer 1

Changing to Set is the best solution. However, if you cannot not replace the List with Set (like in my case, there was a heavy use of JSF tags specific to Lists), and if you can use Hibernate proprietary annotations, you can specify @IndexColumn (name = "INDEX_COL"). That solution worked better for me, changing to Set would require tons of refactoring.

So, your code would be something like this:

@IndexColumn (name = "INDEX_COL")
private List<BillPaidDetails> billPaidDetailses = new ArrayList<BillPaidDetails>();

@IndexColumn (name = "INDEX_COL")
private List<BillProduct> billProductList = new ArrayList<BillProduct>();

As Igor suggested in the comments, you could also create proxy methods to return the lists. I haven't tried that, but would be a good alternative if you cannot use Hibernate proprietary annotations.