Conversion.....

[Vasiq Molvizadah]

This question is from the SCJP6 book...

    
class Dims
{
	public static void main(String[] args)
	{
		int[][] a = {{1,2,3}, {3,4}};
line	1.	int[] b = (int []) a[1];
		Object o1 = a;
line	2.	int[] [] a2 = (int[] []) o1;
line	3.	int[] b2 = (int []) o1;
		System.out.println(b[1]);
	}
}

I've 2 question

1. Is this possible "(int[]) a[1]" ...or is it just to confuse it.

2. At line 3, why it didn't show that o1 is an array of array not array, why it was shown at the runtime..

[Jim Hoglund]

If 'a' is a two dimension array (int[][]) then each element is a one dimension array (int[]).
So casting this way is not necessary; yes, just to confuse you. On your second question,
the compiler only knows 'o1' as an Object so it thinks the cast is okay. But at run time the
JVM knows that 'o1' is a 2-d array.

Jim ... ...

[Vasiq Molvizadah]

Jim Hoglund wrote:If 'a' is a two dimension array (int[][]) then each element is a one dimension array (int[]).
So casting this way is not necessary; yes, just to confuse you. On your second question,
the compiler only knows 'o1' as an Object so it thinks the cast is okay. But at run time the
JVM knows that 'o1' is a 2-d array.

Jim ... ...

Ok buddy thanks a lot for the solution, so even you are preparing for the SCJP exam (on your signature), same here buddy

[Rob Spoor]

I think this thread fits better in our SCJP forum. Moving there.