Note on allocationSize parameter of @SequenceGenerator while using JPA
I ran into what I thought as an issue while I was using the sequence ID generation strategy in JPA. The JPA provider I am using is Hibernate. I think sharing my experience will save someone some time. To use a sequence (For e.g. Oracle sequence) to generate values and assign them to the ID field of your persistence object, you will following something like this: @Id @Column(name = "ITEM_ID") @GeneratedValue(strategy = GenerationType.SEQUENCE, generator="ItemIdSeqGenerator") @SequenceGenerator(name="ItemIdSeqGenerator", sequenceName="ITEM_ID_SEQ", allocationSize=1) private long itemId; This means the following things: The @Id annotation says that the field itemId is a primary key. The @Column annotation says that the corresponding column in the database is ITEM_ID. The @GeneratedValue says that the value that needs to be populated in the itemId should be generated, while that object is persisted. The strategy to generate the value is to