What is the difference between a static method and a non-static method?

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See the code snippets below:

Code 1

public class A {
    static int add(int i, int j) {
        return(i + j);
    }
}

public class B extends A {
    public static void main(String args[]) {
        short s = 9;
        System.out.println(add(s, 6));
    }
}

Code 2

public class A {
    int add(int i, int j) {
        return(i + j);
    }
}

public class B extends A {
    public static void main(String args[]) {
    A a = new A();
        short s = 9;
        System.out.println(a.add(s, 6));
    }
}

What is the difference between these code snippets? Both output 15 as an answer.

java
13 Answers
- First we must know that the diff bet static and non static methods 
is differ from static and non static variables : 

- this code explain static method - non static method and what is the diff 

    public class MyClass {
        static {
            System.out.println("this is static routine ... ");

        }
          public static void foo(){
            System.out.println("this is static method ");
        }

        public void blabla(){

         System.out.println("this is non static method ");
        }

        public static void main(String[] args) {

           /* ***************************************************************************  
            * 1- in static method you can implement the method inside its class like :  *       
            * you don't have to make an object of this class to implement this method   *      
            * MyClass.foo();          // this is correct                                *     
            * MyClass.blabla();       // this is not correct because any non static     *
            * method you must make an object from the class to access it like this :    *            
            * MyClass m = new MyClass();                                                *     
            * m.blabla();                                                               *    
            * ***************************************************************************/

            // access static method without make an object 
            MyClass.foo();

            MyClass m = new MyClass();
            // access non static method via make object 
            m.blabla();
            /* 
              access static method make a warning but the code run ok 
               because you don't have to make an object from MyClass 
               you can easily call it MyClass.foo(); 
            */
            m.foo();
        }    
    }
    /* output of the code */
    /*
    this is static routine ... 
    this is static method 
    this is non static method 
    this is static method
    */

 - this code explain static method - non static Variables and what is the diff 


     public class Myclass2 {

                // you can declare static variable here : 
                // or you can write  int callCount = 0; 
                // make the same thing 
                //static int callCount = 0; = int callCount = 0;
                static int callCount = 0;    

                public void method() {
                    /********************************************************************* 
                    Can i declare a static variable inside static member function in Java?
                    - no you can't 
                    static int callCount = 0;  // error                                                   
                    ***********************************************************************/
                /* static variable */
                callCount++;
                System.out.println("Calls in method (1) : " + callCount);
                }

                public void method2() {
                int callCount2 = 0 ; 
                /* non static variable */   
                callCount2++;
                System.out.println("Calls in method (2) : " + callCount2);
                }


            public static void main(String[] args) {
             Myclass2 m = new Myclass2();
             /* method (1) calls */
             m.method(); 
             m.method();
             m.method();
             /* method (2) calls */
             m.method2();
             m.method2();
             m.method2();
            }

        }
        // output 

        // Calls in method (1) : 1
        // Calls in method (1) : 2
        // Calls in method (1) : 3
        // Calls in method (2) : 1
        // Calls in method (2) : 1
        // Calls in method (2) : 1
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