@Basic(optional = false) vs @Column(nullable = false) in JPA

Question

What's the difference between @Basic(optional = false) and @Column(nullable = false) in JPA persistence???

Answer 1

Gordon Yorke (EclipseLink Architecture Committee Member, TopLink Core Technical Lead, JPA 2.0 Expert Group Member) wrote a good answer on this topic so instead of paraphrasing him, I'll quote his answer:

The difference between optional and nullable is the scope at which they are evaluated. The definition of 'optional' talks about property and field values and suggests that this feature should be evaluated within the runtime. 'nullable' is only in reference to database columns.

If an implementation chooses to implement optional then those properties should be evaluated in memory by the Persistence Provider and an exception raised before SQL is sent to the database otherwise when using 'updatable=false' 'optional' violations would never be reported.