Declaration and Access Control in Java - Quiz

Choose the correct statement 
public class Circle{
      private double radius;  
      public Circle(double radius){
            radius = radius;
      }
}

  • A The program has a compilation error because it does not have a main method.
  • B The program will compile, but we cannot create an object of Circle with a specified radius. The object will always have radius 0.
  • C The program has a compilation error because we cannot assign radius to radius.
  • D The program does not compile because Circle does not have a default constructor.

What is the result of compiling and running the following code? 
public class Tester{
	static int x = 4;
	public Tester(){
		System.out.print(this.x); // line 1
		Tester();
	}
	public static void Tester(){ // line 2
		System.out.print(this.x); // line 3
	}
	public static void main(String... args){ // line 4
		new Tester();
	}
}

  • A Compile error at line 1 (static x must be only accessed inside static methods)
  • B Compile error at line 2 (constructors can't be static)
  • C Compile error at line 3 (static methods can't invoke this)
  • D Compile error at line 4 (invalid argument type for method main )

What is the result of compiling and running the following code? 
class Base{
        private Base(){
                System.out.print("Base");
        }
}
public class test extends Base{
        public test(){
                System.out.print("Derived");
        }
        public static void main(String[] args){
                new test();
        }
}

  • A BaseDerived
  • B Derived
  • C Exception is thrown at runtime
  • D Compilation Error

Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code to compile: 
public class Test{   
        public static void main(String args[]){
	        add(); 
		add(1);
		add(1, 2); 
	}

	// insert code here
}

  • A void add(Integer... args){}
  • B static void add(int... args, int y){}
  • C static void add(int args...){}
  • D static void add(int...args){}

What will be the output for the below code? 
static public class Test{
      public static void main(String[] args){
            char c = 'a';

            switch(c){
                  case 65 : System.out.println("one");break;
		  case 'a': System.out.println("two");break;
		  case 3  : System.out.println("three");
            }	
      }
}

  • A one
  • B two
  • C Compile error - char can't be permitted in switch statement.
  • D Compile error - Illegal modifier for the class Test; only public, abstract & final are permitted.

A method within a class is only accessible by classes that are defined within the same package as the class of the method. Which one of the following is used to enforce such restriction?
  • A Declare the method with the keyword public.
  • B Declare the method with the keyword private.
  • C Declare the method with the keyword protected.
  • D Do not declare the method with any accessibility modifiers.

What will be the output for the below code? 
public class Test{
      static{
            int a = 5; 
      }

      public static void main(String[] args){
            System.out.println(a);
      }
}

  • A Compile with error
  • B 5
  • C 0
  • D Runtime Exception

What is the output for the below code ? 
public class A{
      static{
            System.out.println("static");
      }

      {
            System.out.println("block");
      }

      public A(){
            System.out.println("A");
      }

      public static void main(String[] args){
            A a = new A();
      }
}

  • A A block static
  • B static block A
  • C static A
  • D None of these

What will be the output? 
public class Test{
      public static void main(String[] args){
            String value = "abc";
            changeValue(value);
            System.out.println(value);
      }

      public static void changeValue(String a){
            a = "xyz";
      }
}

  • A abc
  • B xyz
  • C Compilation fails
  • D Compilation clean but no output

Determine Output: 
class MyClass{
      static final int a = 20;

      static final void call(){
            System.out.println("two");
      }
	
      static{
            System.out.println("one");
      }
}

public class Test{
      public static void main(String args[]){
            System.out.println(MyClass.a);
      }
}

  • A one
  • B one two
  • C one two 20
  • D one 20