How is this illegal

Question

a) int i[] = new int[2]{1,2};
b) int[] i = new int[]{1,2,3}{4,5,6}; 

I know we cannot give size of an array at declaration . But in statement(a) we

Answer 1

int i1[] = new int[]{1,2};
int[][] i2 = new int[][]{{1,2,3},{4,5,6}};