json - How can i cast LinkedHashTreeMap to string type? -

json data

{   "id": 8428514522228612,   "name": "order acknowledgment",   "columns": [     {       "id": 7701511984703364,       "index": 0,       "title": "order#",       "type": "text_number",       "primary": true     }, {       "id": 2072012450490244,       "index": 1,       "title": "order date",       "type": "date"     }   ] } 

creating java object , able getid value

myjsonobject1 obj = gson.fromjson(line, myjsonobject1.class); system.out.println(obj.getid()); 

as columns object array , need loop through , columns key , pair values. need columns id,so trying below code

    singlemap nextactioninfomap = new gson().fromjson((string) col,singlemap.class); int column_id = nextactioninfomap.getid(); system.out.println(column_id);   class myjsonobject1 {  private string id; private string name; private object[] columns;  public object[] getcolumns() {     return columns; }  public void setcolumns(jsonobject[] columns) {     this.columns = columns; }  public void setid(string id) {     this.id = id; }  public void setname(string name) {     this.name = name; }  public string getid() {     return id; }  public string getname() {     return name; } 

}

public class singlemap {  private int id; private int index; private string title; private string type; private string primary;  public int getid() {     return id; } public void setid(int id) {     this.id = id; } public int getindex() {     return index; } public void setindex(int index) {     this.index = index; } public string gettitle() {     return title; } public void settitle(string title) {     this.title = title; } public string gettype() {     return type; } public void settype(string type) {     this.type = type; } public string getprimary() {     return primary; } public void setprimary(string primary) {     this.primary = primary; } 

}

but getting:

java.lang.classcastexception: com.google.gson.internal.linkedhashtreemap cannot cast java.lang.string 

how can resolve issue?

if change columns property in myjsonobject1 of type singlemap[] or list<singlemap> instead of object[] gson should parsing in 1 go, no need second pass explicitly parse each column.

class myjsonobject1 {    private singlemap[] columns;    public singlemap[] getcolumns() {     return columns;   }    public void setcolumns(singlemap[] columns) {     this.columns = columns;   } //... }