@XmlAccessorType(XmlAccessType.FIELD)
        @XmlType(name = "")
        public static class TransactionData {
            @XmlAttribute(name = "post_dt", required = true)
            @XmlSchemaType(name = "date")
            protected XMLGregorianCalendar rgstrSlsPostDt;
            @XmlAttribute(name = "sls_tm", required = true)
            @XmlSchemaType(name = "time")
            protected XMLGregorianCalendar slsTm;

// getter setter
    }

XML Request
<TransactionData post_dt="2001-01-01" sls_tm="12:00:00"/>

JSON Request : Not working
"TransactionData " : {
post_dt="2001-01-01" ,
sls_tm="12:00:00"
}

JSON Working Request
"TransactionData " : {
 "PostDt" : "2001-01-01",
  "slsTm":"2012-10-01T09:45:00.000+02:00"
}