Spring Data PageImpl not returning page with the correct size?

To extend stites' answer, a PagedListHolder is the way to go and here is how:

List<String> list = // ...

// Creation
PagedListHolder page = new PagedListHolder(list);
page.setPageSize(10); // number of items per page
page.setPage(0);      // set to first page

// Retrieval
page.getPageCount(); // number of pages 
page.getPageList();  // a List which represents the current page

If you need sorting, use another PagedListHolder constructor with a MutableSortDefinition.

After learning more about how Spring Data works I ended up using @Query annotations on my methods inside the JpaRepository implementations to properly query the DB and filter the results, eliminating the need to use a stream and then convert back to Page.

Here's how the code above would look in case anyone needs an example:

@Query("select p from Produtos p where p.prodNome = ?1")
public Page<Produtos> productsListByName(String prodNome, Pageable pageable)

Im aware of Spring's findBy methods but sometimes the method names become really difficult to read depending on the amount of parameters so I just stuck to JPQL.

Doing it this way the Page's content will always have up to the maximum amount of elements defined by you in the Spring configuration.

I also use a custom implementation of PageImpl, I'm not at work right now and don't have access to the code, but I'll post it whenever I can.

Edit: Custom implementation can be found here

PageImpl is not intended to perform any kind of pagination of your list. From the docs you can see that it's just the "basic Page implementation" which almost sounds like what you want, but it's really misleading.

Use PagedListHolder which is a simple state holder for handling lists of objects, separating them into pages.