I want to use hashmap in a java class which produces XML format, but I am getting JAXB exceptions -

this java class have use hash map getting key-value:

@xmlrootelement public class combo {      private map<combo, list<combo>> businessdomainandbusinesssubdomainspair = new hashmap<combo, list<combo>>();      public map<combo, list<combo>> getbusinessdomainandbusinesssubdomainspair() {         return businessdomainandbusinesssubdomainspair;     }     public void setbusinessdomainandbusinesssubdomainspair(             map<combo, list<combo>> businessdomainandbusinesssubdomainspair) {         this.businessdomainandbusinesssubdomainspair = businessdomainandbusinesssubdomainspair;     } } 

but in angular code getting error on debug:

i tried using linkedhashmap still getting error. can 1 please suggest solution this.