SCJP Sun Certified Java Programmer MCQ 2

Question 1

What is the output of: System.out.println(1 + 2 + "3" + 4 + 5);

Accepted Answer

3345

Answer

Left-to-right evaluation: 1+2=3, then 3+"3"="33", then "33"+4="334", then "334"+5="3345".

Question 2

Which access modifier allows a member to be accessed only within its own package and by subclasses?

Accepted Answer

protected

Answer

The 'protected' modifier grants access within the same package and to subclasses in other packages.

Question 3

What happens when you try to call a method on a null reference in Java?

Accepted Answer

NullPointerException is thrown

Answer

Calling any method on a null reference at runtime throws a NullPointerException.

Question 4

Which of the following correctly declares a two-dimensional array in Java?

Accepted Answer

int[][] arr = new int[2][3];

Answer

The correct syntax is 'int[][] arr = new int[2][3];' which declares and allocates a 2x3 array.

Question 5

What is the default value of an instance variable of type boolean in Java?

Accepted Answer

false

Answer

Instance variables of type boolean default to false if not explicitly initialized.

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