java - In JPA, what does setting a column's nullable to false actually do?

Question

In JPA, if a column isn't nullable, it must have a default value. So if I say

@Column(nullable=false)
Boolean isExpired;

Would it default to true or false? What if it's an Integer or a Long or a String? Is there any way to specify this?

Answer 1

@Column(nullable=false) simply means that you should always supply value to that field when inserting or updating. If you want to specify a default value you can always add this:

 @Column(columnDefinition = "boolean default false")

But as per your question, if you will not define a specific value for that field (through columnDefinition), it will still be null and will prompt an error during DB insert or update if it's null.