Sun Certified Java Programmer MCQ Flashcards

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

Answer: 3345

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

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

Answer: protected

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

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

Answer: NullPointerException is thrown

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

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

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

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

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

Answer: false

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

Which keyword is used to prevent method overriding in Java?

Answer: final

Declaring a method as 'final' prevents it from being overridden in any subclass.

What will be the result of 7 % 3 in Java?

Answer: 1

The modulo operator returns the remainder: 7 divided by 3 is 2 with remainder 1.