com.google.gson.JsonSyntaxException when parsing simple JSON string

Question

I am trying to parse the following JSON string into a class using Gson:

{"email":"leerling@rocgilde.nl","screenname":"Leerling","username":"leerling"}

From what I've read in the docs, its a necessity to design your classes exactly like your JSON, so I did:

public class UserDetails {
    private String email;
    private String screenname;
    private String username;
}

How is it, that something this basic, causes a com.google.gson.JsonSyntaxException?

Thanks.

** EDIT ** As requested, my usage of the Gson library:

details = gson.fromJson(res, UserDetails.class);

The res variable points to the JSON given at the top of the question.

Also, my full stack trace:

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.wesleypeeters.fysio, PID: 5625
                  com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 2
                      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:176)
                      at com.google.gson.Gson.fromJson(Gson.java:803)
                      at com.google.gson.Gson.fromJson(Gson.java:768)
                      at com.google.gson.Gson.fromJson(Gson.java:717)
                      at com.google.gson.Gson.fromJson(Gson.java:689)
                      at com.wesleypeeters.fysio.users.User.<init>(User.java:51)
                      at com.wesleypeeters.fysio.activities.LoginActivity$ProcessLogin.onPostExecute(LoginActivity.java:155)
                      at android.os.AsyncTask.finish(AsyncTask.java:660)
                      at android.os.AsyncTask.-wrap1(AsyncTask.java)
                      at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:677)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6077)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                   Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 2
                      at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:374)
                      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:165)
                      at com.google.gson.Gson.fromJson(Gson.java:803) 
                      at com.google.gson.Gson.fromJson(Gson.java:768) 
                      at com.google.gson.Gson.fromJson(Gson.java:717) 
                      at com.google.gson.Gson.fromJson(Gson.java:689) 
                      at com.wesleypeeters.fysio.users.User.<init>(User.java:51) 
                      at com.wesleypeeters.fysio.activities.LoginActivity$ProcessLogin.onPostExecute(LoginActivity.java:155) 
                      at android.os.AsyncTask.finish(AsyncTask.java:660) 
                      at android.os.AsyncTask.-wrap1(AsyncTask.java) 
                      at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:677) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6077) 
                      at java.lang.reflect.Method.invoke(Native Method)

@Compass as stated in the edit, `res` points to the JSON string earlier given. So it's a `String` with the value `{"email":"leerling@rocgilde.nl","screenname":"Leerling","username":"leerling"}` — welsipieters, Nov 15 '16 at 21:52

score 4 · Accepted Answer · edited May 23 '17 at 12:01

4

It seems likely that you are stripping the braces out of the res variable. Your error message typically indicates it's expecting a { but it's getting a ".

"Expected BEGIN_OBJECT but was STRING at line 1 column 1"

edited May 23 '17 at 12:01

Community

1
1

answered Nov 15 '16 at 21:49

Dave S

3,210
1
16
30

Tried logging it to my console, ` Log.d("UserJson", res);` equals: `D/UserRestlt: "{"email":"leerling@rocgilde.nl","screenname":"Leerling","username":"leerling"}"` – welsipieters Nov 15 '16 at 21:56
3

it looks like there are beginning and trailing quotes in your string object, you might try trimming them off. – Dave S Nov 15 '16 at 21:57
1

Thanks! I missed those. Accepted. – welsipieters Nov 15 '16 at 21:59

score -1 · Answer 2 · answered Nov 15 '16 at 21:53

-1

Expected BEGIN_OBJECT but was STRING at line 1 column 2

This tells us that there is a problem with the string you have passed it. It expects a { at the beginning, and it seems like you did provide it. Is it possible that the string you are passing to GSON isn't formatted to ignore the quotes? Try using Log.d() to print out the res variable and check it for errors

answered Nov 15 '16 at 21:53

coldblade2000

25
1
8

`Log.d("UserJson", res);` equals: `D/UserRestlt: "{"email":"leerling@rocgilde.nl","screenname":"Leerling","username":"leerling"}"` – welsipieters Nov 15 '16 at 21:55
Dave S is correct. Those quotes before and after the string aren't supposed to be there. I used Log.d on my own app, using your string and I had a different output: – coldblade2000 Nov 15 '16 at 22:01
D/hello: {"email":"leerling@rocgilde.nl","screenname":"Leerling","username":"leerling"} – coldblade2000 Nov 15 '16 at 22:01

com.google.gson.JsonSyntaxException when parsing simple JSON string

2 Answers2