How to test if JSON object is empty in Java

Question

The JSON object I\'m receiving looks like this:

[{\"foo1\":\"bar1\", \"foo2\":\"bar2\", \"problemkey\": \"problemvalue\"}]

What I\'m trying

Answer 1

If you're okay with a hack -

obj.toString().equals("{}");

Serializing the object is expensive and moreso for large objects, but it's good to understand that JSON is transparent as a string, and therefore looking at the string representation is something you can always do to solve a problem.

Answer 2

I have added isEmpty() methods on JSONObject and JSONArray()

 //on JSONObject 
 public Boolean isEmpty(){         
     return !this.keys().hasNext();
 }

...

//on JSONArray
public Boolean isEmpty(){
    return this.length()==0;        
}

you can get it here https://github.com/kommradHomer/JSON-java

Answer 3

If empty array:

.size() == 0

if empty object:

.length() == 0