Entity classes from Database wizard does not generate @GeneratedValue(strategy=GenerationType.IDENTITY) for identity column.

If a table has 
CREATE TABLE(ID BIGINT generated always as identity NOT NULL);

the wizard generated code now is:

@Id
@Column(name = "ID", nullable = false)
private BigInteger id;

It should be this:

@Id
@Column(name = "ID", nullable = false)
@GeneratedValue(strategy=GenerationType.IDENTITY)
private BigInteger id;

Otherwise, JPA exceptions will be thown when a new row is added to this table via JPA persistance.