Java Quiz

1.

Which of the following is a valid keyword

2.

Can constructor return a value?

3.

What could be the output of the following program.

class Main {
	public static void main(String args[]) {   
		System.out.println(getNum());
	} 
	
	public int getNum() {
		return 12;
	}
}

4.

Which of the following operator cannot be applied for integer operands?

5.

Which of the following is not a builtin datatype?

6.

What is the value of i that is printed?

public class Sample {
	
	public static void main(String[] args) {
		int i;
		System.out.println(i);
	}
}

7.

Which of the following is not an inbuilt package?

8.

What is the output of the following program:

public class Main {
	
	public static void main(String[] args) {
		int sum = 0;
		for(int i=0;i<10;i++) {
			sum = i;
		}
		System.out.println(sum);
	}
}

9.

Which of the following code can be used to add two integers?

10.

In the following program, code block 1 runs fine while code block 2 throws NullPointerException. Why?

public class Sample {
	
	public static void main(String[] args) {
		String s = null;
		
		// code block 1
		if(s != null && s.length() < 10) {
			System.out.println("");
		} else {
			System.out.println("s is null");
		}
		
		// code block 2
		if(s.length()>10) {
			System.out.println("s have length > 10");
		}
		
	}
}

11.

Method Overloading is an example of

12.

What is the output of following program?

public class Sample {
	
	public static void main(String[] args) {
		if(2) {
			System.out.println("true");
		} else {
			System.out.println("false");
		}
		
	}
}

13.

What is the output of the following code.

public class Sample {

	public static void main(String[] args) {
		System.out.println(5 & 9);
	}

}

14.

What could be the output of following program?

import java.util.ArrayList;

public class Sample {
	
	public static void main(String[] args) {
		ArrayList numbers = new ArrayList();
		numbers.add(1);
		numbers.add(2);
		numbers.add(3);
		
		int sum = 0;
		
		numbers.forEach(number ->{
			sum = sum + number;
		});
		
		System.out.println(sum);
		
	}
}

15.

Which of the following is preferred while programming with Threads

16.

Which is the final state in an Object Life-cycle?

17.

Method Overriding is an example of

18.

Is 'String[] args' mandatory in the definition of main method?

19.

Which of the Exception is thrown when the following code is run?

public class Sample {
    public static void main(String[] args) {
        String[] names = new String[3];
        names[0] = "Sherlock";
        names[1] = "Watson";
        names[2] = "Mary";
        System.out.println(names[4]);
    }
}