xml parsing - JAXB XmlJavaTypeAdapter unmarshal method not being called -

i trying marshal/unmarshal color xml. jaxb project had example code doing exact thing via xmljavatypeadapter https://jaxb.java.net/guide/xml_layout_and_in_memory_data_layout.html.

the marshaling works fine , output expect:

<?xml version="1.0" encoding="utf-8" standalone="yes"?> <beanwithcolor>     <foreground>#ff0000ff</foreground>     <name>clevername</name> </beanwithcolor> 

however, when trying go xml object unmarshal method never called. can provide insight why? after unmarshalled foreground color null , have confirmed debugger unmarshal never being called:

beanwithcolor{foreground=null, name='clevername'} 

scce:

@xmlrootelement public class beanwithcolor { private string name; private color foreground;  public beanwithcolor() {  }  public beanwithcolor(color foreground, string name) {     this.foreground = foreground;     this.name = name; }  @xmljavatypeadapter(coloradapter.class) public color getforeground() {     return this.foreground; }  public void setforeground(color foreground) {     this.foreground = foreground; }  public string getname() {     return name; }  public void setname(string name) {     this.name = name; }  @override public string tostring() {     final stringbuilder sb = new stringbuilder("beanwithcolor{");     sb.append("foreground=").append(foreground);     sb.append(", name='").append(name).append('\'');     sb.append('}');     return sb.tostring(); }  public static void main(string[] args) {     beanwithcolor bean = new beanwithcolor(color.blue, "clevername");      try {         stringwriter writer = new stringwriter(1000);         jaxbcontext context = jaxbcontext.newinstance(beanwithcolor.class);         final marshaller marshaller = context.createmarshaller();         marshaller.marshal(bean, writer);         system.out.println("marshaled xml: " + writer);          final unmarshaller unmarshaller = context.createunmarshaller();         beanwithcolor beanwithcolor = (beanwithcolor) unmarshaller.unmarshal(new stringreader(writer.tostring()));         system.out.println("beanwithcolor = " + beanwithcolor);     } catch (jaxbexception e) {         e.printstacktrace();     }  }  static class coloradapter extends xmladapter<string, color> {     public color unmarshal(string s) {         return color.decode(s);     }      public string marshal(color color) {         return '#' + integer.tohexstring(color.getrgb());     } } } 

i suspect xmladapter being called unmarshal color.decode method failing (this happens when debugged code).

color.decode("#ff0000ff"); 

results in following:

exception in thread "main" java.lang.numberformatexception: input string: "ff0000ff"     @ java.lang.numberformatexception.forinputstring(numberformatexception.java:48)     @ java.lang.integer.parseint(integer.java:461)     @ java.lang.integer.valueof(integer.java:528)     @ java.lang.integer.decode(integer.java:958)     @ java.awt.color.decode(color.java:707) 

you can set validationeventhandler on unmarshaller hook on failures. default jaxb impl wouldn't report problem.

the fix

the coloradapter.marshal method needs fixed return correct value.

string rgb = integer.tohexstring(color.getrgb()); return "#" + rgb.substring(2, rgb.length());