Java diamond with numbers
Before going into any coding I would give you a quick hack for the diamond problem . Instead of making so many for looping and columns and keeping track of variables the diamond problem is a variant of a maths problem. 
HERE 

1*1 = 1
11*11 = 121
111*111 = 12321
1111*1111 = 1234321 


and so on. SO if you use this formula you just need one for loop for spaces and one for increasing your num*10 +1 where num is 1 and then squaring it and you will get the diamond pattern. If you want I can code it for you but since you asked for an easier method this is the best you can get.