hibernate: how to select all rows in a table

Becuase you have used nativeQuery so you need to transfer result by using setResultTransormer method.

Query query = manager.createNativeQuery("SELECT * FROM " + tableName + ";");
query.setResultTransformer(Transformers.aliasToBean(LogEntry.class))
ArrayList<LogEntry> entries = (ArrayList<LogEntry>) query.getResultList();

You can use session.createCriteria(MyEntity.class).list(); for example.

ref: Retrieving all rows of a table without HQL?

For starters, you should try to take advantage of HQL, Hibernate Query Language. In the example you gave above, you are trying to execute a native SQL query. The reason you are getting the ClassCastException is that the native query is circumventing the framework and returning raw Objects instead of the type you want.

Try using this code instead for your SELECT *:

String hql = "from LogEntry";
Session session = entityManagerFactory.openSession();
Query query = session.createQuery(hql);
List<LogEntry> logEntries = query.list();      // no ClassCastException here