Try the following:

int[][] multi = new int[5][10];

... which is a short hand for something like this:

int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];

Note that every element will be initialized to the default value for int, 0, so the above are also equivalent to:

int[][] multi = new int[][] {
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};

... or, more succinctly,

int[][] multi = {
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};

That’s because Java is not C language.
When you write int arr[][] = {{1, 2, 3, 4}, {4, 3, 2, 1}};, you declare and initialize a multidimensional array of 2 by 4. It is equivalent to the C language initialization you proposed (int arr[2][4] = {{1, 2, 3, 4}, {4, 3, 2, 1}};)

In Java, we preferably declare arrays in a Java-style manner:

int[][] arr = {{1, 2, 3, 4}, {4, 3, 2, 1}};

where int[][] is just a type identifier, we cannot specify size.
Moreover, in Java, we can initialize a 2D array that is not rectangular:

int[][] arr = {{1, 2, 3, 4}, {4, 3}};

If you want to declare an array of specific size, but don’t want to specify all it’s values at once, the only solution is to use new:

int[][] arr = new int[2][4];
arr[0][0] = 1;

The best way is probably to just declare and assign all values at once. As shown here. Java will automatically figure out what size the array is and assign the values to like this.

int contents[][] = { {1, 2} , { 4, 5} };

Alternatively if you need to declare the array first, remember that each contents[0][0] points to a single integer value not an array of two. So to get the same assignment as above you would write:

contents[0][0] = 1;
contents[0][1] = 2;
contents[1][0] = 4;
contents[1][1] = 5;

Finally I should note that 2 by 2 array is index from 0 to 1 not 0 to 2.

Hope that helps.

Change int plate[7][7] to int[][] plate or int plate[][]. Both are correct.