Create an object with JSON - Exception received

Question

Given a string keyString, I do in my Java program the following:

ObjectId key = new Gson().fromJson(keyString, ObjectId.class);

But for this line I get this exception:

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 3

What does that mean, and what I can do to solve this?

Basically it could be any string given by user, but for the sake of the discussion, I got this error when keyString was "abc" — DanielY
– DanielY, Commented Jul 14, 2013 at 18:35

Wand Maker · Accepted Answer · 2013-07-14 18:43:46Z

2

It means your JSON does not start with "{". Objects in JSON look something like this:

{
  "name" : "john"
}

answered Jul 14, 2013 at 18:43

Wand Maker

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Comments

Avi · Accepted Answer · 2013-07-14 18:43:26Z

1

The fromJson method awaits a json object. This means a string in json format and specifically it needs to start with { (and not [).

This is valid:

{ 'id': '1234'}

This is not valid:

[{ 'id': '1234'}]

This is also not valid:

abc

answered Jul 14, 2013 at 18:43

Avi

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