Analyze the following code: public class Test1 {
Public Object max(Object o1, Object o2) {
If ((Comparable)o1.compareTo(o2) = 0) {
Return o1;
}
Else {
Return o2;
}
}
}
A) The program has a syntax error because Test1 does not have a main method.
B) The program has a syntax error because o1 is an Object instance and it does not have the compareTo method.
C) The program has a syntax error because you cannot cast an Object instance o1 into Comparable.
D) The program would compile if ((Comparable)o1.compareTo(o2) = 0) is replaced by (((Comparable)o1).compareTo(o2) = 0).
E) b and d are both correct.

Question

Analyze the following code: public class Test1 {
Public Object max(Object o1, Object o2) {
If ((Comparable)o1.compareTo(o2) >= 0) {
Return o1;
}
Else {
Return o2;
}
}
}
A) The program has a syntax error because Test1 does not have a main method.
B) The program has a syntax error because o1 is an Object instance and it does not have the compareTo method.
C) The program has a syntax error because you cannot cast an Object instance o1 into Comparable.
D) The program would compile if ((Comparable)o1.compareTo(o2) >= 0) is replaced by (((Comparable)o1).compareTo(o2) >= 0).
E) b and d are both correct.

Quizplus · Accepted Answer

Option B is correct because Object class does not have the method compareTo(), so it will give a compilation error.
Option C is incorrect because casting to Comparable is allowed in Java, so there is no syntax error.
Option D is correct because when trying to cast o1 into Comparable, the compiler doesn't know if the method is present in Object or in a subclass of Object. Therefore, we must apply a cast to the object before invoking the method. Hence, ((Comparable) o1).compareTo(o2) is the correct syntax.
Option A is incorrect because not having the main method is not a syntax error. It's only necessary if we want to execute the program as a stand-alone Java application. So, it's not a compilation error but might be a runtime error if we try to run the program directly.

Analyze the Following Code: Public Class Test1