jpa - When is an explicit JOIN required in JPQL? -

consider following jpa 2.0-compliant jpql queries:

select p   postaladdress p   join p.constituent c  c.id = :constituentid  order p.type.displayorder 

...and:

select p   postaladdress p   join p.constituent c   join p.type t  c.id = :constituentid  order t.displayorder 

in both cases, p.type @manytoone relationship entity (postaladdresstype).

the difference in 2 queries in first 1 there no explicit join postaladdress postaladdresstype. implied, guess, through p.type.displayorder snippet in where clause. in second, there explicit join.

are these queries equivalent?

are equivalent to:

select p   postaladdress p  p.constituent.id = :constituentid  order p.type.displayorder 

...?

it seems so. in these cases, explicit joins (between postaladdress , constituent, , between postaladdress , postaladdresstype) in way (other readability , explicitness)?

for completeness, understand join required if path expression evaluates collection; i'm not (at moment :-)) interested in case.

it's required each time want left join , not inner join.