Java: Why does this swap method not work?
java
Solution
This doesn't have anything to do with immutability of integers; it has to do with the fact that Java is Pass-by-Value, Dammit! (Not annoyed, just the title of the article :p )
To sum up: You can't really make a swap method in Java. You just have to do the swap yourself, wherever you need it; which is just three lines of code anyways, so shouldn't be that much of a problem :)
Thing tmp = a;
a = b;
b = tmp;
Problem
I have the following code: ``` public class Main { static void swap (Integer x, Integer y) { Integer t = x; x = y; y = t; } public static void main(String[] args) { Integer a = 1; Integer b = 2; swap(a, b); System.out.println("a=" + a + " b=" + b); } } ``` I expect it to print a=2 b=1, but it prints the opposite. So obviously the swap method doesn't swap a and b values. Why?