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I want to annotate a field in my jaxb generated class with this annotation - @XmlElement(required = false). Which attribute in the XSD would generate my field with this annotation?. I can't hand type this as the JAXB classes are auto generated using Maven every time a build is run.

My jaxb version is xjc 2.2.4-2

Thanks

Ganga Aloori
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  • My requirement is to make the field optional. I understand that if I declare the field to be `micOccurs=0` in the XSD it would do the job. But when I did so, xjc is not adding the `@XmlElement(required = false)` annotation by default to the field in the jaxb class. – Ganga Aloori Apr 15 '14 at 12:02
  • Another interesting observation is that when I hand type the annotation to the field in the jaxb class and use JDK's `schemagen` to tool to generate the schema from jaxb classes, I see that the field is added with `minOccurs=0` attribute in the generated schema – Ganga Aloori Apr 15 '14 at 12:07

1 Answers1

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When an element has minOccurs="0" the corresponding @XmlElement has required=false. Note that false is the default value of the required attribute so it may not actually appear in the generated annotation.

UPDATE

Based on your comment:

Let me explain my actual problem. I'm using Jackson to generate the JSON from the JAXB classes. Issue is when the element is not present in the xml, I see the json output with the field name as 'pip' and value as null. I am actually expecting the field 'pip' to be absent from my json output as I declared it to be minOccurs=0 in the XSD. Can't figure out if it's an issue with JAXB or Jackson. Interestingly when I annotate the field explicitly with required=false in the jaxb class, I see my expected output with the field being absent

This is an issue with Jackson not handling the default value of the required property on the @XmlElement annotation correctly.

bdoughan
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  • Thanks Blaise. Exactly that's what I was hoping but that's the case here. Following are the code snippets. XSD `` JAXB `protected List pip;` – Ganga Aloori Apr 15 '14 at 12:11
  • @GangaAloori - I have update my answer with some info that should help. – bdoughan Apr 15 '14 at 12:15
  • Thanks again. Helpful. Let me explain my actual problem. I'm using Jackson to generate the JSON from the JAXB classes. Issue is when the element is not present in the xml, I see the json output with the field name as 'pip' and value as null. I am actually expecting the field 'pip' to be absent from my json output as I declared it to be `minOccurs=0` in the XSD. Can't figure out if it's an issue with JAXB or Jackson. Interestingly when I annotate the field explicitly with `required=false` in the jaxb class, I see my expected output with the field being absent – Ganga Aloori Apr 15 '14 at 12:26
  • @GangaAloori - I have updated my answer. This is an issue with Jackson not handling the default value of the `required` attribute on the `@XmlElement` annotation correctly. – bdoughan Apr 15 '14 at 13:15
  • Thanks for the update. JAXB doesn't generate `@XmlElement` annotation at all for that field. I've posted the element declaration in XSD and the generated field in JAXB class in my previous comment above. – Ganga Aloori Apr 15 '14 at 13:37