Java does not support call by reference. You can make "var" a member of the class and do something like this:
public class Example {
public static int var;
public static void main(String []args){
var = 5;
function1();
System.out.println(var);
var = 5;
function2(var);
System.out.println(var);
}
public static void function1(){
var = var * var;
System.out.println(var);
}
public static void function2(int v){
int v2 = v * v;
System.out.println(v2);
}
}
Output is:
25
25
25
5