How to make a dataset with JSON to make 2 charts

I've got a problem with the dataset function. I use the Netbeans plugin and a JsonDataSource.

In fact I want to make 2 maybe 3 charts:

- 1 pieChart

- 1 lineChart

When i tried without dataset, I've got an error who says:

java.lang.IllegalArgumentException: Null 'key' argument. from these error,

I understood that i must have the 2 data in each jsonobject...

But here's my JSON:

[
{"extention":"zip","label":"9,09 %","value":6},
{"extention":"rtf","label":"34,85 %","value":23},
{"extention":"doc","label":"6,06 %","value":4},
{"count":27,"day":"02/09"},
{"count":1,"day":"02/08"},
{"count":5,"day":"02/07"}
]

I can change the json if I must ... Can you help me ?