Test : Java 11

This test contains 10 questions based on Java.
Each question answered correctly awards you 1 point and each incorrect answer has a penalty of -0.25 points, no points are deducted for unattempted answers.

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You Get +1 for each correct answer and -0.25 for each incorrect answer

Time Left - minutes :seconds

Which keyword is used by method to refer to the object that invoked it?

import	catch
abstract	this

D

The methods wait() and notify() are defined in

java.lang.String	java.lang.Runnable
java.lang.Thread	java.lang.Object

D

Which of these keywords is used to refer to member of base class from a sub class?

upper	super
this	None of the mentioned

B

What is the output of this program?

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

Thread[5,main]	Thread[New Thread,5]
Thread[New Thread,5,main]	Thread[main,5,main]

C

What is the output of this 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");
            }
        }
    }

true	false
Main thread interrupted	None of the mentioned

C

public class Test { public void foo() { assert false; /* Line 5 */ assert false; /* Line 6 */ } public void bar() { while(true) { assert false; /* Line 12 */ } assert false; /* Line 14 */ } } What causes compilation to fail?

Line 5	Line 6
Line 12	Line 14

D

Option D is correct. Compilation fails because of an unreachable statement at line 14. It is a compile-time error if a statement cannot be executed because it is unreachable. The question is now, why is line 20 unreachable? If it is because of the assert then surely line 6 would also be unreachable. The answer must be something other than assert. Examine the following: A while statement can complete normally if and only if at least one of the following is true: - The while statement is reachable and the condition expression is not a constant expression with value true. -There is a reachable break statement that exits the while statement.

What is the output of relational operators?

Integer	Boolean
Characters	Double

B

What will be the output of the program?

public class Test 
{
    public static int y;
    public static void foo(int x) 
    {
        System.out.print("foo ");
        y = x;
    }
    public static int bar(int z) 
    {
        System.out.print("bar ");
        return y = z;
    }
    public static void main(String [] args ) 
    {
        int t = 0;
        assert t > 0 : bar(7);
        assert t > 1 : foo(8); /* Line 18 */
        System.out.println("done ");
    }
}

bar	bar done
foo done	Compilation fails

D

The foo() method returns void. It is a perfectly acceptable method, but because it returns void it cannot be used in an assert statement, so line 18 will not compile.

What is the output of this program?

class box {
        int width;
        int height;
        int length;
        int volume;
        box() {
            width = 5;
            height = 5;
            length = 6;
        }
        void volume() {
             volume = width*height*length;
        } 
    }    
    class constructor_output {
        public static void main(String args[])
        {
            box obj = new box();
            obj.volume();
            System.out.println(obj.volume);        } 
        }
   }

100	150
200	250

B

What is the output of this program?

 class Relational_operator {
        public static void main(String args[])
        {
            int var1 = 5; 
            int var2 = 6;
            System.out.print(var1 > var2);
        } 
    }

0	1
false	true

C

Finish Test