JPA/JPQL Ad Hoc Join - jpa

Question

My question is similar to other related questions except I am using Spring Data and want to return a custom object. Though the custom object i want to return has no reference to many items, the many items do have a reference to my custom object.
database:
CREATE TABLE tree (id integer, type text, leave_color text, category integer);
CREATE TABLE tree_category (id integer, name text);
INSERT INTO tree_category VALUES (1, "Tall");
INSERT INTO tree_category VALUES (2, "Short");
INSERT INTO tree VALUES (1, "Evergreen", "green", 1);
INSERT INTO tree VALUES (2, "Oak" , "green", 1);
INSERT INTO tree VALUES (3, "Purple Tree" , "purple", 2);
INSERT INTO tree VALUES (3, "Short Green Tree" , "green", 2);
Java:
class TreeCategory {
int id;
String name;
//EAGER fetching set
List<Tree> trees;
}
class Tree {
int id;
String type;
String leaveColor;
int categoryId;
}
Spring Data Query:
#Query(value="select tc from TreeCategory tc "
+ "join Tree t on t.categoryId = tc.id "
+ "where t.leaveColor = 'green'"
Collection<TreeCategory> getGreenLeavesByCategory();
It keeps returning TreeCategoryS filled with everything.
i want the "Tall" category with Evergreen and Oak but
"Short" category to only have "Short Green Tree".
how do i accomplish this?

Answer 1

i figured out the answer a couple days ago but someone else may run into this so i'll post. join fetch solved the problem. not sure why i have to do the distinct. i should do show-sql just to see what the query is that is generated.
#Query(value="select distinct tc from TreeCategory tc "
+ "join fetch Tree t "
+ "where t.leaveColor = 'green'"
Collection<TreeCategory> getGreenLeavesByCategory();