How to work with Persistence Context or EntityManager so that memory does not get filled?

To avoid memory overflow when working with Persistence Context or EntityManager in JPA/Hibernate, you need to manage the lifecycle of entities and clear the context:

• Use EntityManager.clear() or EntityManager.detach(entity) to remove unnecessary objects from the context and free memory.
• For large volumes of data, process them in batches, clearing the Persistence Context after each batch.
• In transactions, avoid holding the Persistence Context with a large number of entities for a long time.
• When using Hibernate, you can configure batch size and disable automatic caching if necessary.

Example of clearing the context during batch processing:

for (int i = 0; i < entities.size(); i++) {
    entityManager.persist(entities.get(i));
    if (i % batchSize == 0) {
        entityManager.flush();
        entityManager.clear();
    }
}
entityManager.flush();
entityManager.clear();

This approach helps control memory usage and prevents leaks.