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":"[email protected]","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":"[email protected]","screenname":"Leerling","username":"leerling"} — sushibrain
– sushibrain, Commented Nov 15, 2016 at 21:52

Community · Accepted Answer · 2017-05-23 12:01:27Z

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, 2017 at 12:01

CommunityBot

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answered Nov 15, 2016 at 21:49

Dave S

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3 Comments

sushibrain Over a year ago

Tried logging it to my console, ` Log.d("UserJson", res);` equals: D/UserRestlt: "{"email":"[email protected]","screenname":"Leerling","username":"leerling"}"

Dave S Over a year ago

it looks like there are beginning and trailing quotes in your string object, you might try trimming them off.

sushibrain Over a year ago

Thanks! I missed those. Accepted.

coldblade2000 · Accepted Answer · 2016-11-15 21:53:30Z

-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, 2016 at 21:53

coldblade2000

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3 Comments

sushibrain Over a year ago

Log.d("UserJson", res); equals: D/UserRestlt: "{"email":"[email protected]","screenname":"Leerling","username":"leerling"}"

coldblade2000 Over a year ago

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 Over a year ago

D/hello: {"email":"[email protected]","screenname":"Leerling","username":"leerling"}

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