Static vs. non-static errors!

Question

I dont understand why this doesn't work. Could someone explain the concept behind this error, and perhaps a solution, or another way of going about this?
error:
test.java:3: non-static method add(int,int) cannot be referenced from a static context
add(1,2);
^
1 error
public class test {
   public static void main(String[] args) {
      add(1,2);
   public int add(int a, int b) {
      int c = a+b;
      return c;
}

Answer 1

You need to make your add() static:
public static int add(int a, int b)
Anything you reference in a static method - a method or a variable - that is defined ooutside of the static method must be defined as static. For example:
public class test
int x = 0;
static int y =0;
public static void main(String[] args)
{      add(1,2); 
System.out.println(x) // will cause an error - non-static variable referenced in static class
System.out.println(y) // is okay
public int add(int a, int b)
{      int c = a+b;      return c;  
}