i am not understanding java code

i got a question, could any of you help me in this.

here the java code

if (/^\s*$/.test(a) ? 0 : /^[],:{}\s\u2028\u2029]$/.test(a.replace(/\["\/bfnrtu]/g, "@").replace(/"[^"\\n\r\u2028\u2029\x00-\x08\x0a-\x1f]"|true|false|null|-?\d+(?:.\d*)?(?:[eE][+-]?\d+)?/g, "]").replace(/(?:^|:|,)(?:[\s\u2028\u2029]*[)+/g, ""))) {

and the value of "a" is putted in EVAL(+a+)

Now the problem is that i am not getting understand that what the above java's if code is doing. :(

no idea.