What does the this keyword do?

Question

i don't really understand this code very well, can anyone give me a link or a little explanation that would help me with it? I'm not sure what the this keyword does, and the toString method is puzzling as well.
thanks.
public class Friend
     protected String name;
     protected String telephone;
     protected Friend next;
     static Friend list;
     public static void print() {
     Friend friend = list;
     if(friend == null) System.out.println("The list is empty.");
     else do {
     System.out.println(friend);
     friend = friend.next;
     } while (friend != null);
     public Friend(String name, String telephone)
     this.name = name;
     this.telephone = telephone;
     this.next = list;
     list = this;
     public String toString()
     return new String(name+":\t"+telephone);
class TestFriend
     public static void main(String args[])
     Friend.print();
     new Friend("Anita Murray", "388-1095");
     new Friend("Bill Ross", "283-9104");
     new Friend("Nat Withers", "217-5912");
     Friend.print();
}

Answer 1

about the code in post 1, is there any other code
that could replace what's inside the friend method
but would still print the same output?
for example could i replace "this.name = name;" etc
with anything else?In the context of that constructor, there are two name variables--the parameter and the member variable. The parameter is what was passed into the c'tor, and the member varaible is part of the state of the current object--the object being initialized.
So, when we just say "name", it means the parameter, and if we want to refer to the name variable that's part of the object, then we say "this.name"--that is, the name varaible belonging to "this" object (the "current" object).
If there were no local variable or parameter called "name", then instead of "this.name" we could just say "name" to refer to the current object's name variable, because there would be no ambiguity.