overridden and overloading question

[Pawanpreet Singh]

Hi everybody, i have one doubt regarding following question.

class Animal {
void eat(Object o){
System.out.println("In Animal Object");
}
}

class Horse extends Animal{
void eat(Object o){
System.out.println("In Horse Object");
}

void eat(String str){
System.out.println("In Horse String");
}
}

public class Test {
public static void main(String[] args){
Animal a=new Horse(); // Line 1
a.eat("grass"); // Line 2
}
}

Output is "In Horse Object"...

As we are calling the method with string parameter, so void eat(String str) of Horse should be called.

Please explain that actual concept behind this.

[Keith Lynn]

Because a is a reference of type Animal, the compiler is going to look for the method eat in Animal. Since eat(Object o) is overridden in the subclass Horse, and Horse is the runtime type of the object referred to by a, the method eat(Object o) in Horse is going to be called.

[Deepak Bala]

Try this instead. You need to override the String version of the function to achieve the expected result.

   
class Animal {
void eat(String str){
System.out.println("In Animal String");
}
}
 
class Horse extends Animal{
void eat(Object o){
System.out.println("In Horse Object");
}
 
void eat(String str){
System.out.println("In Horse String");
}
}
 
public class Test {
public static void main(String[] args){
Animal a=new Horse(); // Line 1
a.eat("grass"); // Line 2
}
}