Question

on passing object reference to static method m1() why it does not become null and why last statement doesn’t give errror. Output is X

 class I {
        private String name;
        public String name() {            
            return name;
        }
        public I (String s) {            
            name = s;            
        }
    }

    class J {
        public static void m1 (I i){
            i = null;
        }
        public static void main (String[] arg)
        {
            I i = new I("X");
            m1(i);
            System.out.print(i.name());
        }
    }

Answer 1

Java is pass by value so scope of i is limited to m1()

public static void m1 (I i){ // i is copied from i which is in main method but it is another variable whose scope lies within m1() only

    i = null;  // original i in main lies in main() method scope

}

If you change name of i in method m1(), confusion will be lesser like :

public static void m1 (I iObj){ 
    iObj = null;  // i in main() method still points to Object

}