How to return null value to a variable from a null object using Groovy

Hi,

This is my response:

"English":[

{

"Book":

{

"type":"normal",

null,

null,

"unit":"S"

"value":"10"

}

}

]

Here i have to check if  I'm getting null then i have to move to other line, Until i get some value, have to skip.

When i'm trying to assign it to variable, i'm getting null value exception.

Can you please help me how to handle this and move on to next line.

Regards,

Jagadish.