Consider

public static void main(String[] args) {

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

    System.out.println(foo.length); //2
    System.out.println(foo[0].length); //3
    System.out.println(foo[1].length); //4
}

Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.

This will give you the length of the array at index i

pathList[i].length

It's important to note that unlike C or C++, the length of the elements of a two-dimensional array in Java need not be equal. For example, when pathList is instantiated equal to new int[6][], it can hold 6 int [] instances, each of which can be a different length.

So when you create arrays the way you've shown in your question, you may as well do

 pathList[0].length

since you know that they all have the same length. In the other cases, you need to define, specific to your application exactly what the length of the second dimension means - it might be the maximum of the lengths all the elements, or perhaps the minimum. In most cases, you'll need to iterate over all elements and read their lengths to make a decision:

for(int i = 0; i < pathList.length; i++)
{
    int currLen = pathList[i].length;
}

Try using array[0].length, this will give the dimension you're looking for (since your array is not jagged).

These outputs are perfectly correct. You have a 3-dimensional array of length 2 x 3 x 4 so for all valid indexes i, j :

• a.length is 2
• a[i].length is 3
• a[i][j].length is 4

Fundamentally speaking, a two-dimensional array is nothing more than an array of arrays. So this:

int t2[][] = new int[5][10] ;

is really doing this:

int t2[][] = new int[5][];
for (int i = 0; i < t2.length; i++)
{
    t2[i] = new int[10];
}

Thus in reality, you can assign t2[x] in the same way as you're assigning any other array element.

NOTE: You are not extending the length of the array by saying t2[0] = new int[12]. You are creating a new one, which means that if you have done any assignments to t2[0][x], then they will be lost unless you copy them over yourself.

which 3?

You've created a multi-dimentional array. nir is an array of int arrays; you've got two arrays of length three.

System.out.println(nir[0].length); 

would give you the length of your first array.

Also worth noting is that you don't have to initialize a multi-dimensional array as you did, which means all the arrays don't have to be the same length (or exist at all).

int nir[][] = new int[5][];
nir[0] = new int[5];
nir[1] = new int[3];
System.out.println(nir[0].length); // 5
System.out.println(nir[1].length); // 3
System.out.println(nir[2].length); // Null pointer exception