Demonstrate Two Dimensional Array - Nested For Loops

Java Code:

// Demonstrate a two-dimensional array
class TwoDArray {
public static void main(String args[]) {
int twoD[] [] = new int[4] [5];
int i, j, k = 0;

[Code] .....

Output:

0 1 2 3 4
5 6 7 8 9
10 11 12 13 14
15 16 17 18 19

(1) I don't understand how repeating the loop creates the structure of the output. Taking the second loop away and putting the "System.out.print(twoD[i] [j] + " " );" under k++ creates the output to print a number on each line. How do I write the code not having the second loop, assigning k to each value that is moved through the grid then printing it out but having the output the same?

Java Code:

for(i=0; i<4; i++)
for(j=0; j<5; j++) {
twoD[i][j] = k;
k++;
System.out.print(twoD[i] [j] + " " );
System.out.println();
} mh_sh_highlight_all('java');

(2) I don't understand why you can't put a new line sandwiched between the first for loop

Java Code:

for(i=0; i<4; i++)
System.out.println();
for(j=0; j<5; j++) {
twoD[i][j] = k;
k++; mh_sh_highlight_all('java');
It compiles, but I get the message:

" Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
at TwoDArray.main(TwoDArray.java:11) "