Thanks, just a couple questions. What does "flush" refer to, or mean?
and also, what does the \n  mean in the quote?  Thanks for your help!

Cool thanks I'll try it. Also, im so extremely noob, that i don't know
exactly what you mean by init all variables to 0? Can you give me an
example from my code? thanks

Yes, it is, and not a good one.

The better rule is to initialize variables to their initial value.  If that
happens to be 0 (or equivalent), good (albeit completely unnecessary to state
explicitly for instance or class variables).  If it isn't 0 (or equivalent),
then why initialize to a different value from its initial value?

In the case of the OP:

better would have been to initialize to the initial value (which is only 0 if
gumballs's initial value is 0 and kids's isn't):

 System.out.print("How many gumballs? How many kids? ");

 int gumballs = myScanner.nextInt();
 int kids = myScanner.nextInt();
 int gumballsPerKid = (kids == 0? 0 : gumballs / kids);

[snip]

Please do NOT initialize all variables to 0 in a Java program!

You should not declare your variables until they are first needed and
can be assigned.  If possible, its good practice to declare them final.
This ensures that they will only ever be initialized once, even if you
go through different branches to initialize them.

final int pageSize;
if (pageNumber == 0) {
   pageSize = 10;
} else {
   pageSize = 20;
}
someOtherObject.doSomethingWithPageSize(pageSize);
Better yet, if you can initialize a variable to two different values,
but only use one, make it into a method:

private int getPageSize() {
    if (pageNumber == 0) {
       return 10;
    } else {
       return 20;
    }
}

// then you can use:
final int pageSize = getPageSize();
someOtherObject.doSomethingWithPageSize(pageSize);

Or even better, "inline" that variable (don't use the variable, just use
what you assigned to it, since it has a meaningful name now)

someOtherObject.doSomethingWithPageSize(getPageSize());

Even if you call getPageSize a few times, its better design.  If and
only if you find that calling that method slows down your application
beyond a reasonable level should you "optimize" to saving the value.