Java Online Test

1. Default value of autoFlush attribute is?

2. What is true of final class?

3. What will be the output of the following Java code?

public class Shape
{
	public int area()
       {
		return 1;
	}
}
public class Square extends Shape
{
	public int area()
       {
		return 2;
	}
}
public class Rectangle extends Shape
{
	public int area()
       {
		return 3;
	}
}
Class Main{
    public static void main(String[] args)
    {
	        Shape square = new Square();
     	 Shape rect = new Rectangle();
    	 square = rect;
    	 System.out.println(square.area());
    }
}

4. What type of protocol is HTTP?

5. Which of these methods can be used to obtain the reference to the container that generated a ContainerEvent?

6. Which of these keywords must be used to handle the exception thrown by try block in some rational manner?

7. Which of these package is used for remote method invocation?

8. Which class is a library of functions to perform arithmetic operations of BigInteger and BigDecimal?

9. What is the range of short data type in Java?

10. Which of these method of class StringBuffer is used to find the length of current character sequence?

11. What is the maximum size of cookie?

12. What will be the output of the following Java code?

   
    class isNaN_output 
    {
        public static void main(String args[]) 
        {
            Double d = new Double(1 / 0.);  
            boolean x = d.isNaN();
            System.out.print(x);
        }
    }

13. What are generic methods?

14. Which of these method is a rounding function of Math class?

15. What will be the output of the following Java program?

 
    class output 
    {
        public static void main(String args[])
        { 
           String s1 = "Hello";
           String s2 = s1.replace('l','w');
           System.out.println(s2);
        }
    }

16. What will be the output of the following Java code?

 
    class evaluate 
    {
        public static void main(String args[]) 
            {
	        int arr[] = new int[] {0 , 1, 2, 3, 4, 5, 6, 7, 8, 9};
	        int n = 6;
                n = arr[arr[n] / 2];
	        System.out.println(arr[n] / 2);
            } 
    }

17. Which of these constructors is used to create an empty String object?

18. What will be the output of the following Java code?

    import java.util.*;
    public class genericstack <E>
    {
        Stack <E> stk = new Stack <E>();
	public void push(E obj)
        {
            stk.push(obj);
	}
	public E pop()
        {
            E obj = stk.pop();
	    return obj;
	}
    }
    class Output
    {
        public static void main(String args[])
        {
            genericstack <Integer> gs = new genericstack<Integer>();
            gs.push(36);
            System.out.println(gs.pop());
        }
    }

19. Which of the following classes can catch all exceptions which cannot be caught?

20. Which of these methods of Character wrapper can be used to obtain the char value contained in Character object.

21. Which of these data member of HttpResponse class is used to store the response from an http server?

22. Which method returns the elements of Enum class?

23. What will be the output of the following Java program?

 
    class newthread extends Thread
    {
	Thread t;
	String name;
	newthread(String threadname)
        {
	    name = threadname;
	    t = new Thread(this,name);
	    t.start();
	}
	public void run()
        {
        }
     
    }
    class multithreaded_programing
    {
        public static void main(String args[])
        {
	    newthread obj1 = 	 new newthread("one");
	    newthread obj2 =	 new newthread("two");
            try
            {
                obj1.t.wait();	
                System.out.print(obj1.t.isAlive());
            }
            catch(Exception e)
            {
	    System.out.print("Main thread interrupted");
            }
        }
    }

24. What will be the output of the following Java program?

 
    import java.util.*;
    class Bitset 
    {
        public static void main(String args[]) 
        {
            BitSet obj = new BitSet(5);
            for (int i = 0; i < 5; ++i)
                obj.set(i);
            obj.clear(2);
            System.out.print(obj);
        }
    }

25. Which of these keywords is used to refer to member of base class from a subclass?

26. Which of these methods of Byte wrapper can be used to obtain Byte object from a string?

27. What will be the output of the following Java program?

 
    import java.net.*;
    class networking 
    {
        public static void main(String[] args) throws Exception 
        {
            URL obj = new URL("https://www.sanfoundry.com/javamcq");
            URLConnection obj1 = obj.openConnection();
            System.out.print(obj1.getContentType());
        }
    }

Note: Host URL is written in html and simple text.

28. What will be the output of the following Java program?

 
    import java.util.*;
    class Collection_iterators 
    {
        public static void main(String args[]) 
        {
            LinkedList list = new LinkedList();
            list.add(new Integer(2));
            list.add(new Integer(8));
            list.add(new Integer(5));
            list.add(new Integer(1));
            Iterator i = list.iterator();
            Collections.reverse(list);
	    Collections.shuffle(list);
            i.next();
            i.remove();
            while(i.hasNext())
	        System.out.print(i.next() + " ");
        }
    }

29. Which of these methods can be used to get reference to a component that was removed from a container?

30. Which of these packages contains abstract keyword?

31. When destroy() method of a filter is called?

32. What will be the output of the following Java code?

 
    class array_output 
    {
        public static void main(String args[]) 
        {
            int array_variable[][] = {{ 1, 2, 3}, { 4 , 5, 6}, { 7, 8, 9}};
            int sum = 0;
            for (int i = 0; i < 3; ++i)
                for (int j = 0; j <  3 ; ++j)
                    sum = sum + array_variable[i][j];
            System.out.print(sum / 5);
        } 
    }

33. Which of these methods are used to read in from file?

34. Which of these method of Double wrapper can be used to check whether a given value is infinite or not?

35. Which of the below is false about java coding?

36. What will be the output of the following Java code?

 
    class multithreaded_programing
    {
        public static void main(String args[])
        {
            Thread t = Thread.currentThread();
            t.setName("New Thread");
            System.out.println(t);        
        }
    }

37. What is the alternative of using finally to close resource?

38. Which of the following is not a decision making statement?

39. Which of these classes encapsulate runtime environment?

40. Which of these are constants defined in WindowEvent class?

41. What will be the output of the following Java program?

    
    class output 
    {
        public static void main(String args[])
        {
            String a = "hello i love java";
            System.out.println(a.indexOf('e')+" "+a.indexOf('a')+" "+a.lastIndexOf('l')+" "+a.lastIndexOf('v'));
        }
    }

42. Which of these keywords is used to prevent content of a variable from being modified?

43. Which of the below is invalid identifier with the main method?

44. What will be the output of the following Java program?

 
import java.io.*;
public class filesinputoutput
{
    public static void main(String[] args)
    {
        String obj  = "abc";
        byte b[] = obj.getBytes();
        ByteArrayInputStream obj1 = new ByteArrayInputStream(b);
        for (int i = 0; i < 2; ++ i)
        {
            int c;
            while((c = obj1.read()) != -1)
            {
                if(i == 0)
                {
                    System.out.print(Character.toUpperCase((char)c));
                }
                System.out.print((char)c);
            }
        }
    }
}	

45. Which of these is a method of ObjectInput interface used to deserialize an object from a stream?

46. Which of these methods can be used to obtain a static array from an ArrayList object?

47. Which of this package is used for analyzing code during run-time?

48. Which of these packages contain all the collection classes?

49. Thread priority in Java is?

50. Which one of the following is a class loader?