Static method never allows a non-static method call directly.
Reason: Static method belongs to its class only, and to nay object or any instance.
So, whenever you try to access any non-static method from static method inside the same class: you will receive:
"An object reference is required for the non-static field, method or property".
Solution: Just declare a reference like:
public class <classname>
{
static method()
{
new <classname>.non-static();
}
non-static method()
{
}
}