Recursive Function, Pass by "reference"

Question

I need to create a function and build an Arraylist.
public void buildList (String s, Arraylist list) {
....//code specific to application
list.add(something);
buildList(somestring, list);
public void anotherFunction(){
buildList(str, myList);
Will myList contain the values that are added? Is this only a copy of the list?

Answer 1

Java always passes by value.
(Now it gets confusing)
In this case it passes a reference by value.
The method gets its own variable for storing the reference to the list in.
ie it is the equivalent of saying
Arraylist list = myList;
It doesn't copy the entire list, it just gets a reference to it.
If you change the contents of the list by calling list.add() then original looks like it was updated, as they point to the same thing.
If you execute
list = new ArrayList();
Then list becomes distinct and seperate from the myList variable in the calling procedure.
If java was pass by reference, when you execute list = new ArrayList it would also change the value of the variable in the calling procedure. That doesn't happen.
Hope that clears things up,
evnafets