Deductions & credits

Hmm...

So this is what I want to know. If I  withdraw 401k, it counts as my income, right?  

For example, assuming withholding the due taxes,  if I withdraw a total of $15000 ($2500 x 6) until Dec.,  does it simply add to my other income and get taxed when I file the tax returns next year? Or do I pay for the taxes on this 401k withdrawal and, seperately, on my total incomes including the 401k withdrawal?