Java Constructor and Methods - Quiz

The following code contains one compilation error, find it? 
public class Test {
	Test() {    }  // line 1
	static void Test() {  this(); } // line 2  
	public static void main(String[] args) { // line 3
		Test(); // line 4
	}
}

  • A At line 1, constructor Tester must be marked public like its class
  • B At line 2, constructor call
  • C At line 3, compilation error, ambiguity problem, compiler can't determine whether a constructor
  • D At line 4

The variables declared in a class for the use of all methods of the class are called
  • A reference variables
  • B objects
  • C instance variables
  • D None of these

Determine output of the following program. 
public class Test{
           public static void main(String args[]){
                  System.out.println( Math.floor( Math.random( ) ) ) ;
           }
}

  • A 1.0
  • B 10.0
  • C 0.0
  • D 0.5

What is the output for the below code? 
public class Test{
      public static void printValue(int i, int j, int k){
            System.out.println("int");
      }

      public static void printValue(byte...b){
            System.out.println("long");
      }

      public static void main(String... args){
            byte b = 9;
            printValue(b,b,b);
      }
}
  • A long
  • B int
  • C Compilation fails
  • D Compilation clean but throws RuntimeException 

class MyClass{
      MyClass(){
            System.out.print("one");
      }
      public void myMethod(){
            this();
            System.out.print("two");
      }
}
 
public class TestClass{
      public static void main(String args[]){
            MyClass obj = new MyClass();
            obj.myMethod();
      }
}
which one is correct
  • A two one one
  • B one one two
  • C one Exception
  • D Compilation Error

Which of the following options is the best for generating random integer 0 or 1?
  • A (int)Math.random()
  • B (int)Math.random() + 1
  • C (int)(Math.random() + 0.5)
  • D (int)(Math.random() + 0.2)

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 ) ;
       }     
}

  • A 0
  • B 2.0
  • C Compile time error
  • D None of the above

Which of the modifier can't be used for constructors?
  • A public
  • B private
  • C static
  • D protected

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

  • A Won't compile because of line (1); constructor can't be private
  • B Won't compile because of line (5); constructor can't be final
  • C 50
  • D 10 50 

class A{
      A(String s){}

      A(){}
}

1. class B extends A{
2.       B(){}
3.       B(String s){
4.             super(s);
5.       }
6.       void test(){
7.             // insert code here
8.       }
9. }
Which of the below code can be insert at line 7 to make clean compilation ?
  • A A a = new B();
  • B A a = new B(5);
  • C A a = new A(String s);
  • D All of the above