What is JSON and How To Use It

JSON ==> "JSON stands for JavaScript Object Notation".

a). JSON is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for 

     machines  to parse and generate.

b). JSON is language independent.

c). JSON is a form of text.

d). JSON is easy for transfer over network and easy to parse over server side and client side.

e). Basically JSON is a form of key value or name value pair in which each key will be inside double quotes and value will be any thing.

     For example : String, Boolean, Number, Double ,Object and null.

     These types of value will be store as a value in json.

f). JSON is divided in two parts

    [i]  => JSON Object.

    [ii] => JSON Array

First we discussed on JSON Object

 For example i have a class Employee with fields name ,employeeId,age ,active and salary.

If we create JSON object of employe it will be look like as.  

     {       

        "employeeId" : 1,
        "name" : "Ram",
        "salary" : 30000.00,
        "active" : true,
        "age" : null

      }

  Here we notice some points

1. All names are inside quotes.

2. Boolean value can be either true or false without quotes.

3. Integer is a wrapper type object in java it will be null.

4. Salary is double type so it will store without quotes;

5. "{", "}" curly brases shows its a one json object.

Now we discussed on JSON Array.

JSON array is collection of JSON Object.

JSON array are use inside bracket"[ ]".

Inside JSON array we add multiple objects by comma (,) seperated.

Example :- We have three json object of employee. Then JSON array look like as.

[

     {       

        "employeeId" : 1,
        "name" : "Ram",
        "salary" : 30000.00,
        "active" : true,
        "age" : null

     } ,

    {       

        "employeeId" : 2,
        "name" : "Shyam",
        "salary" : 43000.00,
        "active" : true,
        "age" : 40

      },

     {       

        "employeeId" : 3,
        "name" : "Prakhar",
        "salary" : 55555.00,
        "active" : false,
        "age" : 25

      }

]

Here each json object of employee seperated by comma.

Note => We can store JSON data in a file with extension (.json).