How many copies of the object will be created?

Question

Hi folks,
Would anybody tell me how copies of the String objects will be created in the following examples?
List list = new ArrayList(3);
list.add("1");
list.add("2");
list.add("3");
//example 1
String str1 = null;
for (int i=0; i < list.size(); i++) {
str1 = (String)list.get(i);
//example 2
for (int i=0; i < list.size(); i++) {
String str2 = (String)list.get(i);
Thanks!

Answer 1

Example 2 is better style because a variable should be declare in the narrowest possible scope.
This,
String str2 = (String)list.get(i);
actually is a composite statement equivalent to,
String str2; // variable declaration
str2 = (String)list.get(i); // assignment to variable
So you do two things. You declare a variable, and you assign it a reference.
In a high level language the only thing you decide when you declare a variable is its type and its scope. You cannot determine when and where the compiler is to allocate memory for the variable. There's no penalty to declaring a variable inside a loop. The compiler will NOT somehow recreate the variable in each iteration.