Пример последовательностей JPA Insert + Oracle

CREATE TABLE CUSTOMER(
	ID NUMBER(10) NOT NULL,
	NAME VARCHAR2(100) NOT NULL,
	EMAIL VARCHAR2(100) NOT NULL,
	CREATED_DATE DATE NOT NULL,
	CONSTRAINT CUSTOMER_PK PRIMARY KEY (ID)
);

CREATE SEQUENCE customer_seq
  MINVALUE 1
  MAXVALUE 9999999999
  START WITH 4
  INCREMENT BY 1;

package com.mkyong.model;

import javax.persistence.*;
import java.util.Date;

@Entity
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CUST_SEQ")
    @SequenceGenerator(sequenceName = "customer_seq", allocationSize = 1, name = "CUST_SEQ")
    Long id;

    String name;
    String email;

    @Column(name = "CREATED_DATE")
    Date date;

    //...
}