jackson IOException: Can not deserialize Class com.mycompany.models.Person$Address (of type non-static member class) as a Bean

Question

I have a class that looks like this:

public class Person {
    public class Address {
        private String line1;
        private String line2;
        private         


        

Answer 1

Correct, this used to be something you can not do with current Jackson versions (1.8 and earlier). But is it absolutely necessary for inner class to be non-static? If not, just add 'static' in declaration of Address and it'll work fine; problem is with the "hidden" this-pointer that non-static inner classes take via constructor.

Jackson 1.9 will actually supports deserialization of simple uses of non-static inner classes, see this Jira entry.

Answer 2

Because inner classes do not have a default zero argument constructor (they have a hidden reference to the outer/parent class) Jackson cannot instantiate them.

The solution is to use static inner classes:

public class Outer {
    static class Inner {
        private String foo;
        public String getFoo() { return foo; }
    }
}

Original Answer:

There are some issues in implementation and it seems like you can't serialize such classes, see cowtowncoder for details.