Answer Posted / j mathew

class A{
void hallo(){
System.out.println(" hallo of A");
}
}
class B extends A {
void hallo(){ // method overridden.
System.out.println("hallo of B");
}
}
class C extends B {
void hallo(){ // method overridden
System.out.println("hallo of C");
}
}
class Demo {
public static void main(String[] args) {
A a = new A(); // create object of A
B b = new B(); // create object of B
C c = new C(); // create object of C
A r; // create a reference of super class
r=a; // assign object of A to the reference var. r
r.hallo(); // it calls hallo() of class A
r=b; // super class variable can reference a
sub class object.
r.hallo(); // it calls hallo() of class B
r =c; // super class variable can ref. sub
class object.
r.hallo(); // it calls hallo() of class C
}
}

this is how dynamic dispath method works.
overridden methods are resolved at run time rather than
compile time. At compile time it doesn't know which over-
ridden method will be called.
it comes to know at run time, thats why it is called as run
time polymorphism.

What is a variable declaration?

928

---

What is empty string literal in java?

995

---

What is method with example?

1019

---

How do you initialize an arraylist in java?

977

---

What is use of inner class in java?

1039

---

Why do we use regex?

956

---

What is nested class?

950

---

State the difference between strings and arrays.

1143

---

Why is java so important?

1067

---

Can we override constructor in java?

1044

---

Assume a thread has lock on it, calling sleep() method on that thread will release the lock?

1046

---

What is static data type in java?

981

---

What is the difference between normal report & matrix report?

1054

---

Can a class be declared as protected?

959

---

What is ++ a in java?

927

---