When to use Hibernate projections?

Question

I am a little confused about Hibernate\'s projections and criteria. When to use projections and when to use criteria?

Answer 1

Hibernate projections are useful for

1)Fetching only certain columns of the table

2)Performing aggregations like count,sum,max,min,avg.

Fetching only the columns which are needed improves the performance of the query.

Examples of projection

Projections using DTO

Projection List example