Difference between JSONObject and JSONArray

Question

After having a short look at Google I found this link that describes the difference, yet from a syntax point of view.

When would one be preferred over the other in a programming scenario?

Answer 1

When you are working with JSON data in Android, you would use JSONArray to parse JSON which starts with the array brackets. Arrays in JSON are used to organize a collection of related items (Which could be JSON objects).
For example: [{"name":"item 1"},{"name": "item2} ]

On the other hand, you would use JSONObject when dealing with JSON that begins with curly braces. A JSON object is typically used to contain key/value pairs related to one item. For example: {"name": "item1", "description":"a JSON object"}

Of course, JSON arrays and objects may be nested inside one another. One common example of this is an API which returns a JSON object containing some metadata alongside an array of the items matching your query:

{"startIndex": 0, "data": [{"name":"item 1"},{"name": "item2"} ]} 

Answer 2

The difference is the same as a (Hash)Map vs List.

JSONObject:

• Contains named values (key->value pairs, tuples or whatever you want to call them)
  • like {ID : 1}
• Order of elements is not important
  • a JSONObject of {id: 1, name: 'B'} is equal to {name: 'B', id: 1}.

JSONArray:

• Contains only series values
  • like [1, 'value']
• Order of values is important
  • array of [1,'value'] is not the same as ['value',1]

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Example

JSON Object --> { "":""}  JSON Array --> [ , , , ]  {"employees":[     {"firstName":"John", "lastName":"Doe"},     {"firstName":"Anna", "lastName":"Smith"},     {"firstName":"Peter", "lastName":"Jones"} ]}