how to store xml data in to arraylist java -

i have xml file data (not complete xml file)

<header>        <parametercontext>        <parameter>           <name>fileid<name>                                    <value>1001445<value>        </parameter>        <identifier>id</identifier>     </parametercontext>     <parametercontext>          <parameter>          <name>product</name>          <value>ect</ns0:value>      </parameter>      <identifier>productname</identifier>      </parametercontext>                 </header> 

please me store xml data(data of parametercontext elements) in arraylist.

sorry not posting earlier. have 2 classes object , load

public class object{    private arraylist<parametercontext> parameterctx = new arraylist<parametercontext>();      public arraylist<parametercontext> getparameterctx() {     return parameterctx; }    public void setparameterctx(parametercontext parameterctx) {     this.parameterctx.add(parameterctx) ; }   public parameter searchparameter(string name, string identifier,                       arraylist<parametercontext> al) {    for(int = 0; < al.size(); i++) {         if(al.get(i).getidentifier().equalsignorecase(identifier)) {             for(int j = 0; j < al.get(i).getparameter().size(); j++) {                 if(al.get(i).getparameter().get(j).getname().equalsignorecase(name) ) {                     return al.get(i).getparameter().get(j);                 }             }         }     }      return null ; } 

}

and

 public class load{    @xmlelement(name = "parametercontext") protected list<load.parametercontext> parametercontext;   public list<load.parametercontext> getparametercontext() {     if (parametercontext == null) {         parametercontext = new arraylist<load.parametercontext>();     }     return this.parametercontext; }   @xmlaccessortype(xmlaccesstype.field) @xmltype(name = "", proporder = {     "parameter",     "identifier" }) public static class parametercontext {      @xmlelement(name = "parameter", required = true)     protected list<load.parametercontext.parameter> parameter;     @xmlelement(name = "identifier", required = true)     protected string identifier;    public list<load.parametercontext.parameter> getparameter() {         if (parameter == null) {             parameter = new arraylist<load.parametercontext.parameter>();         }         return this.parameter;      }       public string getidentifier() {         return identifier;     }  public void setidentifier(string value) {         this.identifier = value;  }  @xmlaccessortype(xmlaccesstype.field)     @xmltype(name = "", proporder = {         "name",         "value"     })     public static class parameter {          @xmlelement(name = "name", required = true)         protected string name;         @xmlelement(name = "value", required = true)         protected string value;      public string getname() {             return name;         }        public void setname(string value) {             this.name = value;         }         public string getvalue() {             return value;         }        public void setvalue(string value) {             this.value = value;         } 

when use object.searchparameter("field","id",object.getparameterctx()).getvalue());

nullpointerexception coming.(getparameterctx not initialized).before line need initialize right.how initialize?

using jaxb, create class mimics xml

@xmlrootelement(name="header") public class xmlbean {    public list<parametercontext> pc;     public xmlbean() {     }     public list<parametercontext> getpc() {       return pc;    }    public void setpc(list<parametercontext> pc) {       this.pc = pc;    } }  public class parametercontext {       public parameter parameter;       public string identifier;        public parametercontext() {        }       public parameter getparameter() {           return pc;       }       public void setparameter(parameter parameter) {           this.param = param;       }       public string getidentifier() {           return identifer;       }       public void setidentifier(string identifier) {           this.identifier = identifier;       } }  public class parameter {    public string name;    public string value;     public parameter() {     }     public void setname(string name) {       this.name = name;    }     public void getname() {       return name;    }     public void setvalue(string value) {       this.value = value;    }     public void getvalue(string value) {       return value;    } }  public static void main(string[] args) {    inputstream = yourxml    jaxbcontext jaxb = jaxbcontext.newinstace(xmlbean.class);    unmarshaller jaxbunmarshaller = jaxb.createunmarshaller();    xmlbean xml = (xmlbean) jaxbunmarshaller.unmarshal(is);     system.out.println(xml.getparametercontext().get(0).getparam().getname());    system.out.println(xml.getparametercontext().get(0).getparam().getvalue()); } 

something that