I thought arrays had to specify how many elements to use? But in this code it's not....

this is an array declaration and initialization. If you initialize an array to some value, you do not need to explicitly define how many elements to use (i.e the size of the array) because the compiler is able to do it.

Number of elements in this array is specified by a number of tokens delimited by String#split() (in this case, the delimiter is a whitespace - " ").
After creation of an array, it has static size (in contrast to dynamic size structures, like e.g. ArrayList).

gotchya ty guys