Java Quiz

1.

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);
	}
}

2.

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

3.

What is the value of i that is printed?

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

4.

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

5.

What is the output of the following code.

public class Sample {

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

}

6.

Which of the following is a valid keyword

7.

Method Overriding is an example of

8.

Which of the following is not an inbuilt package?

9.

Method Overloading is an example of

10.

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]);
    }
}

11.

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;
	}
}

12.

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");
		}
		
	}
}

13.

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");
		}
		
	}
}

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.

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

16.

Which of the following is not a builtin datatype?

17.

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

18.

Can constructor return a value?

19.

Which of the following is preferred while programming with Threads