The J=2 configuration has to be for two parallel in the same direction pointing vectors. This is because only like this you will be able to get a vector length 1.
The J=0 configuration has a similar reasoning. For this we need two parallel in the opposite direction poiting vectors. This is because for two equally sized vectors, this is the only way to get 0.
Finally the J=1 configuration corresponds to orthogonal vectors. This is because only like this we can make the resulting vector the same size as the two that are being summed.