Java Advance (Level 3)

Q 1.

Which of the following operators can operate on a boolean variable?

1. && 
2. == 
3. ?: 
4. +=

3 & 2 1 & 4 1, 2 & 4 1, 2 & 3

Q 2.

Which of these statements is correct?

true and false are numeric values 1 and 0 true and false are numeric values 0 and 1 true is any non zero value and false is 0 true and false are non numeric values

Q 3.

What will be the output of the following Java code?

class Output {
    public static void main(String args[]) {
        int x, y = 1;
        x = 10;
        if (x != 10 && x / 0 == 0) System.out.println(y);
        else System.out.println(++y);
    }
}

1 2 Runtime error owing to division by zero in if condition Unpredictable behavior of program

Q 4.

What will be the output of the following Java code?

class Output {
    public static void main(String args[]) {
        boolean a = true;
        boolean b = false;
        boolean c = a ^ b;
        System.out.println(!c);
    }
}

0 1 False True

Q 5.

What would be the output of the following code snippet if variable a=10?

if (a <= 0) {
    if (a == 0) {
        System.out.println("1 ");
    } else {
        System.out.println("2 ");
    }
}
System.out.println("3 ");

1 2 2 3 1 3 3

Q 6.

What is true about do statement?

do statement executes the code of a loop at least once do statement does not get execute if condition is not matched in the first iteration do statement checks the condition at the beginning of the loop do statement executes the code more than once always

Q 7.

What is the valid data type for variable “a” to print “Hello World”?

switch (a) {
    System.out.println("Hello World");
}

int and float byte and short char and long byte and char

Q 8.

From where break statement causes an exit?

Only from innermost loop Terminates a program Only from innermost switch From innermost loops or switches

Q 9.

Which of the following is not a valid flow control statement?

exit() break continue return

Q 10.

Which of the following is a valid declaration of an object of class Box?

Box obj = new Box(); Box obj = new Box; obj = new Box(); new Box obj;

Q 11.

Which of these statement is incorrect?

Every class must contain a main() method Applets do not require a main() method at all There can be only one main() method in a program main() method must be made public

Q 12.

What will be the output of the following Java program?

 class main_class 
    { 
        public static void main(String args[]) 
        { 
            int x = 9;
            if (x == 9)
            { 
                int x = 8;
                System.out.println(x);
            } 
        } 
    }

9 8 Compilation error Runtime error

Q 13.

Which of the following statements is correct?

Public method is accessible to all other classes in the hierarchy Public method is accessible only to subclasses of its parent class Public method can only be called by object of its class Public method can be accessed by calling object of the public class

Q 14.

What will be the output of the following Java program?

 class box 
    {
        int width;
        int height;
        int length; 
    }
    class mainclass
    { 
        public static void main(String args[])
        {
            box obj = new box();
            obj.width = 10; 
            obj.height = 2;
            obj.length = 10; 
            int y = obj.width * obj.height * obj.length; 
            System.out.print(y); 
        } 
    }

12 200 400 100

Q 15.

What will be the output of the following Java program?

 class box 
    { 
        int width;
        int height;
        int length;
    }
    class mainclass
    {
        public static void main(String args[]) 
        { 
            box obj1 = new box(); 
            box obj2 = new box(); 
            obj1.height = 1; 
            obj1.length = 2;
            obj1.width = 1; 
            obj2 = obj1;
            System.out.println(obj2.height);
        } 
    }

1 2 Runtime error Garbage value

Q 16.

What will be the output of the following Java program?

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

0 1 Runtime error classname@hashcode in hexadecimal form

Q 17.

What is -Xms and -Xmx while starting jvm?

Initial; Maximum memory Maximum; Initial memory Maximum memory Initial memory

Q 18.

What happens to the thread when garbage collection kicks off?

The thread continues its operation Garbage collection cannot happen until the thread is running The thread is paused while garbage collection runs The thread and garbage collection do not interfere with each other

Q 19.

Which of the below is not a memory leak solution?

Code changes JVM parameter tuning Process restart GC parameter tuning

Q 20.

Garbage Collection can be controlled by a program?

True False

Instruction