check if an object is null

Question

I have a linked list in which first node contains null object. means firstNode.data is equal to null, firstNode.nextPointer = null, firstNode.previousPointer = null.

And I want to check if firstNode is null or not. So I tried-

if(list.firstNode == null){

            //do stuff          
        }

but this doesn't works?

I also tried equals too. Any suggestions?

I tried printing. And I got as-

{null} -- firstNode

Answer 1

I think your firstNode is not null, but its fields are. Try something like this:

if (list.firstNode.data == null) {
    //do stuff          
}

Answer 2

Did you try

if (list.firstNode.data == null) { /* Do stuff */ }