Hibernate 8 + Jakarta Persistence 4: EntityAgent and stateless sessions demo

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b7jUQrypvpE1ix1k7V

output/05-lock-modes-in-entityagent.txt

@@ -0,0 +1,45 @@
+=== H2 ===
+
+get(Book.class, "978-1", OPTIMISTIC)
+  right after get() (1 statement)
+  select b1_0.isbn,b1_0.price,b1_0.publisher_id,b1_0.title,b1_0.version,b1_0.views from book b1_0 where b1_0.isbn=? for update
+  during commit (0 statements)
+  version before: 0, after: 0
+
+get(Book.class, "978-1", OPTIMISTIC_FORCE_INCREMENT)
+  right after get() (2 statements)
+  select b1_0.isbn,b1_0.price,b1_0.publisher_id,b1_0.title,b1_0.version,b1_0.views from book b1_0 where b1_0.isbn=? for update
+  update book set version=? where isbn=? and version=?
+  during commit (0 statements)
+  version before: 0, after: 1
+
+get(Book.class, "978-1", PESSIMISTIC_WRITE)
+  right after get() (1 statement)
+  select b1_0.isbn,b1_0.price,b1_0.publisher_id,b1_0.title,b1_0.version,b1_0.views from book b1_0 where b1_0.isbn=? for update
+  during commit (0 statements)
+  version before: 1, after: 1
+
+get(Book.class, "978-1", PESSIMISTIC_FORCE_INCREMENT)
+  right after get() (2 statements)
+  select b1_0.isbn,b1_0.price,b1_0.publisher_id,b1_0.title,b1_0.version,b1_0.views from book b1_0 where b1_0.isbn=? for update
+  update book set version=? where isbn=? and version=?
+  during commit (0 statements)
+  version before: 1, after: 2
+
+=== HSQLDB ===
+
+get(Book.class, "978-1", OPTIMISTIC)
+  FAILED: org.hibernate.HibernateException: Stateless optimistic locking requires transaction-long row protection; no strategy established for HSQLDialect:2:LOCKING
+
+get(Book.class, "978-1", OPTIMISTIC_FORCE_INCREMENT)
+  FAILED: java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "owner" is null
+
+get(Book.class, "978-1", PESSIMISTIC_WRITE)
+  right after get() (1 statement)
+  select b1_0.isbn,b1_0.price,b1_0.publisher_id,b1_0.title,b1_0.version,b1_0.views from book b1_0 where b1_0.isbn=? for update
+  during commit (0 statements)
+  version before: 0, after: 0
+
+get(Book.class, "978-1", PESSIMISTIC_FORCE_INCREMENT)
+  FAILED: java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "owner" is null
+