One of the common problem while marshaling Java object to XML String using JAXB is the default format of date and time provided by JAXB. When JAXB converts any Date type object or XMLGregorianCalendar to XML String, precisely xsd:dateTime element, it by default prints unformatted date e.g. 2012-05-17T09:20:00-04:30. Since most of the real world, Java application has a requirement to print date in a particular format like dd-MM-yyyy or include date and time in format dd-MM-yyyy HH:mm:ss, it becomes a problem. Thankfully, JAXB is very extensible and provides hooks and adapters to customize marshaling and unmarshaling process. You can define an extension of XmlAdapter to control and customize marshaling and unmarshaling or any Java type depending upon yours need.