What will be the output of the following Java program?
public class BoxDemo
{
public static <U> void addBox(U u,
java.util.List<Box<U>> boxes)
{
Box<U> box = new Box<>();
box.set(u);
boxes.add(box);
}
public static <U> void outputBoxes(java.util.List<Box<U>> boxes)
{
int counter = 0;
for (Box<U> box: boxes)
{
U boxContents = box.get();
System.out.println("[" + boxContents.toString() + "]");
counter++;
}
}
public static void main(String[] args)
{
java.util.ArrayList<Box<Integer>> listOfIntegerBoxes = new java.util.ArrayList<>();
BoxDemo.<Integer>addBox(Integer.valueOf(0), listOfIntegerBoxes);
BoxDemo.outputBoxes(listOfIntegerBoxes);
}
}
public class BoxDemo
{
public static <U> void addBox(U u,
java.util.List<Box<U>> boxes)
{
Box<U> box = new Box<>();
box.set(u);
boxes.add(box);
}
public static <U> void outputBoxes(java.util.List<Box<U>> boxes)
{
int counter = 0;
for (Box<U> box: boxes)
{
U boxContents = box.get();
System.out.println("[" + boxContents.toString() + "]");
counter++;
}
}
public static void main(String[] args)
{
java.util.ArrayList<Box<Integer>> listOfIntegerBoxes = new java.util.ArrayList<>();
BoxDemo.<Integer>addBox(Integer.valueOf(0), listOfIntegerBoxes);
BoxDemo.outputBoxes(listOfIntegerBoxes);
}
}A. 0
B. 1
C. [1]
D. [0]
Answer: Option D
This Question Belongs to Java Program >> Interfaces And Abstract Classes
A. A contract specifying a set of methods that a class must implement
B. A class that cannot be instantiated
C. A class that contains only static methods
D. A subclass of the Object class
In Java, can a class implement multiple interfaces?
A. Interfaces cannot be implemented by classes
B. Only abstract classes can implement interfaces
C. No, a class can only implement one interface
D. Yes, a class can implement multiple interfaces
What is the purpose of an abstract class in Java?
A. To declare abstract methods
B. To provide a base class with common methods and fields
C. To make a class final
D. To declare abstract methods
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