update

Author: ahsannawaz111

src/main/java/io/ipgeolocation/api/IPGeolocationAPI.java

@@ -7,6 +7,7 @@
 
 import com.google.gson.Gson;
 
+import static io.ipgeolocation.api.Strings.isJsonString;
 import static io.ipgeolocation.api.Strings.isNullOrEmpty;
 
 public class IPGeolocationAPI {
@@ -145,6 +146,9 @@ private Map<String, Object> callAPIEndpoint(String endpoint, String urlParams) {
             if(isNullOrEmpty(responseCode) || isNullOrEmpty(jsonString)) {
                 responseCode = "422";
                 jsonString = "{\"message\":\"Something went wrong while parsing IP Geolocation API response\"}";
+            } else if (!isJsonString(jsonString)) {
+                responseCode = "422";
+                jsonString = "{\"message\":\"Connection problem or Invalid response by IP Geolocation API\"}";
             }
         } catch (IOException e) {
             responseCode = "422";
@@ -194,7 +198,7 @@ private Map<String, String> parseConnectionResponse(HttpURLConnection connection
         return responseMap;
     }
 
-    private Map<String, Object> convertJSONStringToMap(String responseCode, String response){
+    private Map<String, Object> convertJSONStringToMap(String responseCode, String response) {
         Gson gson = new Gson();
         Map<String,Object> map = new LinkedHashMap<String, Object>();
 

src/main/java/io/ipgeolocation/api/Strings.java

@@ -1,5 +1,7 @@
 package io.ipgeolocation.api;
 
+import com.google.gson.Gson;
+
 class Strings {
 
     static String nullToEmpty(String s) {
@@ -12,4 +14,17 @@ static String nullToEmpty(String s) {
     static Boolean isNullOrEmpty(String string) {
         return string == null || string.trim().equals("");
     }
+
+    static Boolean isJsonString(String jsonString) {
+        Gson gson = new Gson();
+        try {
+            Object jsonObjType = gson.fromJson(jsonString, Object.class).getClass();
+            if(jsonObjType.equals(String.class)){
+                return false;
+            }
+            return true;
+        } catch (com.google.gson.JsonSyntaxException ex) {
+            return false;
+        }
+    }
 }