java - Gson, how to deserialize array or empty string -

i trying deserialize json array of objects:

[{     "name": "item 1",     "tags": ["tag1"] }, {     "name": "item 2",     "tags": ["tag1","tag2"] }, {     "name": "item 3",     "tags": [] }, {     "name": "item 4",     "tags": "" }] 

my java class looks this:

public class myobject {     @expose     private string name;      @expose     private list<string> tags = new arraylist<string>(); } 

the problem json's tags property can empty string or array. right gson gives me error: com.google.gson.jsonsyntaxexception: java.lang.illegalstateexception: expected begin_array string

how should deserialize json?

i not have control json, comes 3rd pary api.

i not have control json, comes 3rd pary api.

if don't have control on data, best solution create custom deserializer in opinion:

class myobjectdeserializer implements jsondeserializer<myobject> {     @override     public myobject deserialize(jsonelement json, type typeoft, jsondeserializationcontext context) throws jsonparseexception {         jsonobject jobj = json.getasjsonobject();         jsonelement jelement = jobj.get("tags");         list<string> tags = collections.emptylist();         if(jelement.isjsonarray()) {             tags = context.deserialize(jelement.getasjsonarray(), new typetoken<list<string>>(){}.gettype());         }         //assuming there appropriate constructor         return new myobject(jobj.getasjsonprimitive("name").getasstring(), tags);     } } 

what it checks whether "tags" jsonarray or not. if it's case, deserializes usual, otherwise don't touch , create object empty list.

once you've written that, need register within json parser:

gson gson = new gsonbuilder().registertypeadapter(myobject.class, new myobjectdeserializer()).create(); //here json string contains input list<myobject> myobjects = gson.fromjson(json, new typetoken<list<myobject>>(){}.gettype()); 

running it, output:

myobject{name='item 1', tags=[tag1]} myobject{name='item 2', tags=[tag1, tag2]} myobject{name='item 3', tags=[]} myobject{name='item 4', tags=[]}