If you use Gson, in order to parse your response you can create a custom class representing your JSON data, and then you can use a Map.
Note that a Map<String, SomeObject> is exactly what your JSON represents, since you have an object, containing a pair of string and some object:
{ "someString": {...} }
So, first your class containing the JSON data (in pseudo-code):
class YourClass
String type
String status
String icon
int number
String display_number
Then parse your JSON response using a Map, like this:
Gson gson = new Gson();
Type type = new TypeToken<Map<String, YourClass>>() {}.getType();
Map<String, YourClass> map = gson.fromJson(jsonString, type);
Now you can access all the values using your Map, for example:
String GUID = map.keySet().get(0);
String type = map.get(GUID).getType();
Note: if you only want to get the GUID value, you don't need to create a class YourClass, and you can use the same parsing code, but using a generic Object in the Map, i.e., Map<String, Object>.