Java Constructor and Methods - Quiz

Q: What is the expected output?

public class Profile {
         private Profile(int w) { // line 1
                  System.out.print(w);
         }
         public static Profile() { // line 5
                  System.out.print (10);
         }
         public static void main(String args[]) {
                  Profile obj = new Profile(50);
         }
}

Q: What will be the return type of a method that not returns any value?

Q: Which of the modifier can't be used for constructors?

Q: Determine output of the following program.

public class Test{
           public static void main(String args[]){
                  System.out.println( Math.floor( Math.random( ) ) ) ;
           }
}

Q: What is the output of the above program?

class Num  {
      Num(double x ){
              System.out.println( x ) ;
      }   
}
public class  Test  extends  Num   {
       public static void main(String[] args){
                  Num num = new Num( 2 ) ;
       }     
}

Q: Given the following piece of code:

class Person{
        public int number;
}
public class Test{
        public void doIt(int i , Person p){
                i = 5;
                p.number = 8;
        }
        public static void main(String args[]){
                int x = 0;
                Person p = new Person();
                new Test().doIt(x, p);
                System.out.println(x + " " + p.number);
        }
}

Q: Which of the following statements regarding static methods are correct?

1. Static methods are difficult to maintain, because you can not change their implementation.
2. Static methods can be called using an object reference to an object of the class in which this method is defined.
3. Static methods are always public, because they are defined at class-level.
4. Static methods do not have direct access to non-static methods which are defined inside the same class.

Q: What is the prototype of the default constructor? public class Test { }

Q: What is the output for the below code ?

1. public class A{
2.       int add(int i, int j){
3.             return i+j;
4.       }
5. }
6. public class B extends A{
7.       public static void main(String argv[]){
8.             short s = 9;
9.             System.out.println(add(s,6));
10.      }
11.}

Q:

public class MyClass{ }