Java Quiz

1.

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");
		}
		
	}
}

2.

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

3.

Method Overriding is an example of

4.

Method Overloading is an example of

5.

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

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 is the final state in an Object Life-cycle?

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 is not a builtin datatype?

10.

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);
		
	}
}

11.

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");
		}
		
	}
}

12.

Which of the following is a valid keyword

13.

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

14.

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]);
    }
}

15.

Can constructor return a value?

16.

What is the output of the following code.

public class Sample {

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

}

17.

Which of the following is preferred while programming with Threads

18.

Which of the following is not an inbuilt package?

19.

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;
	}
}