Decisions

Question 1

Where can labels be used?

Answer 1

On loops, switches, if statements

Question 2

Pattern matching variable can also be?

Answer 2

Reassigned into something else inside flow scope

Question 3

Pattern matching variable can also be?

Answer 3

Final

Question 4

What happens if you instanceof check int primitive with Integer?

Answer 4

Casting exception

Question 5

What happens if you instanceof check local variable with same type via pattern matching?

Answer 5

Compile error where variable is already defined

Question 6

What happens if you instanceof check local variable with same supertype via pattern matching?

Answer 6

Compile error that pattern matching variable is supertype of local variable

Question 7

What happens if you instanceof check local variable with same subtype via pattern matching?

Answer 7

It compiles and you have pattern matching variable

Question 8

What is flow scoping?

Answer 8

You can define pattern matching variable while evaluating with instanceof. That variable is only available inside that check statement scope. If you negate instanceof expression, then that variable is available to all other evaluations (if-else if), but not outside evaluations scope

Question 9

What primitives cannot be used in switch statement?

Answer 9

boolean, long, float and double

Question 10

Can switch statement be empty?

Answer 10

Yes

Question 11

Do switch statements support “break”?

Answer 11

Yes

Question 11

Can cases inside switch expression be listed in same line?

Answer 11

Yes

Question 12

Do switch expressions support “break”?

Answer 12

No

Question 13

What are rules regarding ; in switch expressions?

Answer 13

They must appear outside expression and they must appear at the end of each case, instead of block {}. There they must appear inside code block.

Question 14

How does switch expression look like?

Answer 14

• It contains a type, identifier and a switch statement, but cases are comprised of arrows ->, not :. -
• They must contain ; at the end, and at the end of each case, with exception of code blocks {}.

Question 15

What are rules of switch expression?

Answer 15

• It has specific structure, different from pure switch statement
• All possible values of switch variable must be covered by cases, or “default” case must be introduced instead
• If expression returns multiple variable types, then “var” must be used.
• Implicit casting of lower primitives to int is applied if return type is int
• Direct casting of primitives is possible
• Code block {} must yield, cannot be empty

Question 16

How is one way of creating infinite for loop?

Answer 16

for ( ; ; )

Question 17

Can for loop manage variables outside for loop from its “iteration” section?

Answer 17

Yes

Question 17

Can for loops contain more iteration variables?

Answer 17

Yes, in same line, ruled by “in same line initialization” rule

Question 18

Can variables inside for loop’s “initialization” section have same name as local variables?

Answer 18

No, “initialization” section is not isolated scope, it can use local variables