Java not returning array object from list.toArray()

Question

I have a movie class That has a private List<String> reviews = new ArrayList<String>();

On the constructor I set

public Movie()
{
    this.reviews.add("");
}

When I try to add it to a JSON object as so,

JSONObject.put("reviews", this.reviews.toArray(new String[reviews.size()]));

I checked the JSON file and it return "reviews":[Ljava.lang.String;@5cad8086]

What is happening here? I want to put an Array of reviews into the field "reviews" like {"reviews" : ["somestring1", "somestring2"]}

It is a JSONObject where the put method accept the field & value as arguments respectively — Gavin, Oct 28 '15 at 14:50
Do you know what `[Ljava.lang.String;@5cad8086]` represents? Have you at least looked that up? — Sotirios Delimanolis, Oct 28 '15 at 15:21
It is storing the address of the array right but I have no idea why, hence the question — Gavin, Oct 28 '15 at 15:43
Take a look at [this](http://stackoverflow.com/questions/29140402/how-do-i-print-my-java-object-without-getting-sometype2f92e0f4). — Sotirios Delimanolis, Oct 28 '15 at 15:56

score 0 · Accepted Answer · edited May 23 '17 at 12:29

json-simple apparently doesn't support adding array types directly to a JSONObject. When rendering the JSONObject to a String, it simply calls toString on its values (JSONObject is a HashMap).

As such, you're seeing the default String result of invoking toString on an array type. See

How do I print my Java object without getting "SomeType@2f92e0f4"?

The most appropriate solution with json-simple is to create a JSONArray object from your List and add that

JSONArray array = new JSONArray();
array.addAll(reviews);
JSONObject.put("one", array);

assuming JSONObject is a variable that references a JSONObject object.

I'll end this with my opinion that json-simple is a terrible JSON parser/generator library. There are much better alternatives in Gson, Jackson, and even org.json.

score -1 · Answer 2 · answered Oct 28 '15 at 14:35

-1

You have to use this :

Arrays.toString(this.reviews.toArray(new String[reviews.size()]));

answered Oct 28 '15 at 14:35

Rahman

3,755
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This seems to generate `"reviews":"[myString]"` Instead of `"reviews":[{"myReviewString1"}, {myReviewString2}]` – Gavin Oct 28 '15 at 14:49
1

@MaTaKazer What you just posted is invalid json. – Sotirios Delimanolis Oct 28 '15 at 14:50
I wanted something like `{"reviews" : ["somestring1", "somestring2"]}` – Gavin Oct 28 '15 at 15:10

Java not returning array object from list.toArray()

2 Answers2