Java.Hibernate.Beginner.How can i understad that i use HQL or JPQL ?

🔹 1️⃣ Context of your project

• JPQL is used if you’re working with JPA (javax.persistence / jakarta.persistence), e.g.:
  • Your project uses JPA annotations (@Entity, @Id, etc.).
  • You create queries using EntityManager.createQuery().
  • You rely on JPA-standard features like @PersistenceContext, @Transactional.

HQL is used if you’re directly working with native Hibernate API, e.g.:

• Your code uses org.hibernate.Session.createQuery().
• You don’t use JPA’s EntityManager.

🔹 2️⃣ How you build queries
✅ JPQL

TypedQuery<User> query = entityManager.createQuery(
    "SELECT u FROM User u WHERE u.username = :username", User.class);

Uses JPA EntityManager.

Always JPQL.

✅ HQL

List<User> users = session.createQuery(
    "FROM User u WHERE u.username = :username", User.class).list();

Uses Hibernate Session.

Always HQL.

🔹 3️⃣ Query features

• If your queries use Hibernate-specific syntax or functions (e.g., index(), elements(), or certain proprietary operators), that’s HQL — JPQL won’t recognize them.

🔹 4️⃣ Are you using JPA-only annotations?

• If your project uses javax.persistence.EntityManager instead of org.hibernate.Session, you’re definitely in JPQL-land.

🔹 5️⃣ Tools & providers

• If you run your queries in Spring Data JPA repositories, your @Query strings are JPQL.
• If you run your queries directly on Hibernate’s Session API, they’re HQL.

🔹 Bottom line:
✅ JPQL → you use JPA’s EntityManager or @Query in Spring Data JPA → fully portable.
✅ HQL → you use Hibernate’s Session API directly → Hibernate-specific.

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🔹 Key takeaway:
The simplest way to know:

• EntityManager → JPQL
• Session → HQL