Question

If there is a method call MyClass.returnArray() and I iterate over the array using the for-each construct (also called the “enhanced for” loop):

for (ArrayElement e : MyClass.returnArray()) {
   //do something
}

will then the returnArray() method be called for every iteration?

Answer 1

No, it won’t. The result of the first call will be stored in the compiled code in a temporary variable.

From Effective Java 2nd. Ed., Item 46:

Note that there is no performance penalty for using
the for-each loop, even for arrays. In fact, it may offer a slight performance advantage
over an ordinary for loop in some circumstances, as it computes the limit of
the array index only once.