null

false

true

Arrays.fill(matrix,

-1);

Arrays.deepFill(matrix,

-1);

for(int[]

row : matrix) Arrays.fill(row, -1);

null

0

 ArrayIndexOutOfBoundsException

Collections.sort(matrix);

Arrays.sort(matrix);

Arrays.sort(matrix, Comparator.comparingInt(a

-> a[0]));

delete

matrix;

matrix.clear();

matrix

= null;

Collections.reverse(Arrays.asList(matrix));

for(int

i=0;i<matrix.length/2;i++){ int[] temp=matrix[i];

matrix[i]=matrix[matrix.length-i-1]; matrix[matrix.length-i-1]=temp;

}

for(int

i=0;i<matrix.length;i++) Arrays.sort(matrix[i]);

2

3

6

[null,

null, null]

[[I@some_hashcode,

[I@some_hashcode, [I@some_hashcode]

[0,

0, 0]

for(int

row[] : matrix) System.out.print(row);

for(int[]

row : matrix) for(int value : row) System.out.print(value);

for(int

row : matrix) for(int value : row) System.out.print(value);