SCJP Basic 4

Question 1

What happens when you assign a larger numeric type to a smaller one without casting in Java?

Accepted Answer

Compile-time error

Answer

Narrowing conversions require an explicit cast; without one, the compiler produces an error.

Question 2

Which loop is guaranteed to execute its body at least once?

Accepted Answer

do-while

Answer

A do-while loop checks its condition after executing the body, so it always runs at least once.

Question 3

What is the output of: System.out.println("Hello" + 1 + 2);?

Accepted Answer

Hello12

Answer

String concatenation is left-to-right; "Hello" + 1 = "Hello1", then "Hello1" + 2 = "Hello12".

Question 4

Which of the following is true about Java's 'break' statement in a switch block?

Accepted Answer

It prevents fall-through to the next case

Answer

Without break, execution falls through to subsequent cases; break exits the switch block.

Question 5

What is the purpose of the 'this' keyword in Java?

Accepted Answer

It refers to the current object instance

Answer

The 'this' keyword is a reference to the current object within an instance method or constructor.

SCJP - Sun Certified Java Programmer Practice Test