Trouble understanding "BreakWithLabelDemo" (Sun Java Tutorial)

Question

Hi.
I've been slowly working my way through all of the Sun Java tutorials, now I've come across one I just can't wrap my head around.
It's the "BreakWithLabelDemo" tutorial located at [http://java.sun.com/docs/books/tutorial/java/nutsandbolts/branch.html] that is confusing me.
class BreakWithLabelDemo {
    public static void main(String[] args) {
        int[][] arrayOfInts = { { 32, 87, 3, 589 },
                                { 12, 1076, 2000, 8 },
                                { 622, 127, 77, 955 }
        int searchfor = 12;
        int i;
        int j = 0;
        boolean foundIt = false;
    search:
        for (i = 0; i < arrayOfInts.length; i++) {
            for (j = 0; j < arrayOfInts.length; j++) {
if (arrayOfInts[i][j] == searchfor) {
foundIt = true;
break search;
if (foundIt) {
System.out.println("Found " + searchfor +
" at " + i + ", " + j);
} else {
System.out.println(searchfor
+ " not in the array");
Now it's not understanding what the +break+ statement does that's the problem, it's the nested +for+ loops they've used to demonstrate it that is, and in particularly the code.arrayOfInts[i].length;Now, could someone please enlighten me as to what this statement returns to be evaluated against the variable +j+.
For instance does it simply return the length of the array +arrayOfInts+ and if so why is it referencing a specific element within the array denoted by the variable +i+ ? Also the array is multidimensional when it's declared and initialized and yet it's treated as a regular array in the code above? Why doesn't that throw an error?
Any help walking me through this piece of code would be fantastic. Thank you.
-nexus                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Answer 1

int[][] arrayOfInts = ...In effect arrayOfInts is a multidimensional array. But it's important to remember that Java has no notion of array dimension. It's just an array - an array consisting of three things in order: {32, 87, 3, 589}, {12, 1076, 2000, 8}, and {622, 127, 77, 955}. It just so happens that these elements are also arrays.
Because it's just an array arrayOfInts also has a length. The length is three because there's three elements. It doesn't matter that each of the elements has a length 4, arrayOfInts has length 3.
In this particular array the elements are also arrays, so it makes sense to ask what their length is. For instance, the last one, {622, 127, 77, 955}, is just arrayOfInts[2] and it has length 4. We can refer to its length as arrayOfInts[2].length and write code like:
if(arrayOfInts[2].length == 4) {
    // this will be executed for the array in the example
}Where arrays are multidimensional - in the sense that their elements are also arrays - they can be "ragged". For instance
int[][] arrayOfInts = {
    {32, 87, 3, 589},
    {12},
    {622, 127, 77, 955, -1, 42, 5}
};The array elements all have different lengths and that is why the inner for loop uses the expression j<arrayOfInts.length so that it loops through the correct number of elements of the i-th element of [i]arrayOfInts.