JAXB objects initialized with default values

Question

There is little problem with JAXB.

---

Given:

• Java 1.5; jaxb -jars from jaxws-2_0.
• .xsd scheme and genera

Answer 1

For an initialization of the class members from XSD supplied defaults, you can use the default-value-plugin of XJC.

See the website of the plugin.

Note that the ant task definition as explained in that documentation did not work for me. As explained here, the class paths for XJC and the plugin have to be separated. Specifying the path to the plugin when calling it works for me:

<xjc schema="some.xsd" >
    <arg value="-Xdefault-value"/>
    <classpath>
        <pathelement location="lib/xjc-plugins/jaxb2-default-value-1.1.jar"/>
    </classpath>
</xjc>

Answer 2

default value that is in annotations works only after unmarshalling.
unmarshal this

<document>
   <d_int/>
   <d_double/>
   <d_string/>
</document>  

and you will get object with default values (-1, -1.0, "Default")

If you want set default values to marshalling, you should do this

public class Document {
    @XmlElement(name = "d_int", defaultValue = "-1")
    protected int dInt = 100;
    @XmlElement(name = "d_double", defaultValue = "-1.0")
    protected double dDouble = -100;
    @XmlElement(name = "d_string", required = true, defaultValue = "Default")
    protected String dString = "def";
...
}    

jaxb generate default values only for unmarshalling