Java valid declarations of a two-dimensional array

Question

I was going through one App which is suggested for the OCJP exam. I found one question about the two-dimensional array.

Question: Valid declarations of a two-dimensional array.

Options:

int[][] array2D;
int[2][2] array2D;
int array2D[];
int[] array2D[];
int[][] array2D[];

My selection: int[][] array2D; and int[] array2D[] but when I submit my answer it tells me that int[] array2D[] is wrong and correct is int[][] array2D[];

I think the int[][] array2D[]; is incorrect answer.

Am I right?
Is int[] array2D[] recommended in programming?

Your question was so poorly formatted, please do some effort next time. — user180100
– user180100, Commented Feb 9, 2017 at 6:56
1) You are correct. 2) int[] array2D[] is discouraged by the Java Language Specification itself: We do not recommend "mixed notation" in array variable declarations, where bracket pairs appear on both the type and in declarators; nor in method declarations, where bracket pairs appear both before and after the formal parameter list. — Andreas
– Andreas, Commented Feb 9, 2017 at 6:56
JVM wouldn't give you error for this, JVM doesn't know you want it to be treated as 2d array. — Sikorski
– Sikorski, Commented Feb 9, 2017 at 7:09

Akshay · Accepted Answer · 2017-02-09 06:58:48Z

5

The answer to this seems to be both options 1 and 4.

int[][] array2D

is a standard way to declare a 2-d int array.

Although int[] array2D[]; it is not a good practice it will work and will be a valid declaration.

edited Feb 9, 2017 at 6:58

answered Feb 9, 2017 at 6:57

Akshay

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3 Comments

Sikorski Over a year ago

typo in last statement ? int [] array2D [] perhaps ?

Andreas Over a year ago

"not a good practice" is called "we do not recommend" in the JLS. See my comment.

Vimal Panchal Over a year ago

@Akshay agreed with your answer.

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