Any way to differentiate between default null and value null in jackson.xml deserialization?

Question

I want to convert a xml to json using jackson library. Initially, I generated java classes based on the xsd file using jaxb. I wonder how to differentiate between a default null and the null value in the xml.

  <n2:test>
    <address/>
  </n2:test>

  class Test {
    String address; >> give null value
    String IC; >> give null value (default is null)
  }