Scala Test

Scala bytecode can run on top of Java VM. What is the fundamental difference between Java object.clone() and Scala object.copy()?

CLONE() WILL COPY CLASS STRUCTURES BUT NOT THE DATA, WHILE COPY() WILL ALSO COPY DATA INTO NEW OBJECTS.

ONE IS A JAVA OBJECT, THE OTHER IS A SCALA OBJECT.

THERE IS NO DIFFERENCE.

COPY() ALLOWS YOU TO CHANGE VALUES DURING THE COPYING PROCESS; CLONE() DOES NOT.

What is one way to avoid low-level parallelization details?

MONADS

LITERAL FUNCTIONS

PARTIALLY APPLIED FUNCTIONS

PARALLEL COLLECTIONS

What do you use in ScalaTest to see a detailed diagram of error messages when a test fails?

JUNIT

DIAGRAMMEDASSERTIONS

ARGUMENTEXCEPTIONS

ASSERTIONEXCEPTION

What data type would you use to store an immutable collection of objects that contain a fixed number of varying types?

LIST

TUPLE

ARRAY

IMMUTABLECOLLECTION

After defining a function in the interpreter, Scala returns the following. What does the () indicate? myfnc: ()Unit

THE FUNCTION TAKES NO PARAMETERS.

THE FUNCTION RETURNS NO VALUE.

THE FUNCTION HAS NO SIDE EFFECTS.

RETURNING UNIT TYPES TO THE FUNCTION IS A CLOSURES.

What type of number is 1234.e5?

FLOATING POINT

HEXADECIMAL

LONG

SHORT

When you convert a map to a list using the toList method of the map, the result will be of which type?

LIST[(ARRAY, ARRAY)]

LIST

LIST[(COLLECTION, COLLECTION)]

LIST[(STRING, STRING)]

What type of object does this code create? val x = (1234, "Active")

LIST

MAP

ARRAY

TUPLE

Which is a subclass of all classes?

ANYVAL

NULL

ANYREF

METHOD

For the for-yield construct, is the scope separate between for-body and yield-body?

YES AND NO. IT IS DIFFERENT DEPENDING ON THE FOR CONSTRUCT AND WHAT IT DOES.

YES, BECAUSE THE FOR SECTION DOES NOT EXPOSE ITS SCOPE.

NO, BECAUSE FOR-YIELD SHARES THE SAME SCOPE, EVEN THOUGH THEY ARE WITHIN SEPARATE CURLY BRACES.

YES, BECAUSE THEY ARE WITHIN DIFFERENT CURLY BRACES.

What is one way to implement pattern matching on methods?

USING STRING MATCHING

USING CASE CLASSES

USING MONADS

USING REGEX

What term is used to specify a precondition?

ASSERT

PRECONDITION

MUSTHAVE

REQUIRE

Which Scala type may throw an exception or a successfully computed value, and is commonly used to trap and propagate errors?

SCALA.CATCH.THROW

SCALA.UTIL.EXCEPTIONHANDLING

SCALA.UTIL.TRY

SCALA.EXCEPTION.TRYFINALLY

What is the data type of y after this code is executed? val y = (math floor 3.1415 * 2)

DOUBLE

SHORT

BIGINT

INT

When using pattern matching, which character matches on any object?

^

_

*

%

You have created an array using val. Can you change the value of any element of the array—and why or why not?

NO, VAL MAKES THE ARRAY AND VALUES OF THE ARRAY IMMUTABLE.

THE 0TH ELEMENT IS IMMUTABLE AND CANNOT BE MODIFIED. ALL OTHER ELEMENTS CAN BE MODIFIED.

YES, VAL DOES NOT MAKE ARRAYS IMMUTABLE.

YES, THE REFERENCE TO THE ARRAY IS IMMUTABLE, SO THE LOCATION THAT THE ARRAY POINTS TO IS IMMUTABLE. THE VALUES IN THE ARRAY ARE MUTABLE.

What do you call objects with immutable state?

SINGLETONS

STATIONARY OBJECTS

FUNCTIONAL OBJECTS

FIXED OBJECTS

You have written a Scala script. How would you access command-line arguments in the script?

USE THE TUPLE NAMED ARGS.

USE NUMBERED VARIABLES WITH A _ PREFIX—FOR EXAMPLE, _1, _2, AND _3.

USE NUMBERED VARIABLES WITH A $ PREFIX—FOR EXAMPLE, $1, $2, AND $3.

USE THE ARRAY NAMED ARGS.

What does this code return? val x = 3; if (x >2) x = 4 else x = x*2

4

AN ERROR

6

3

Which statement returns a success or failure indicator when you execute this code? val myFuture = Future {runBackgroundFunction() }

COMPLETE(MYFUTURE)

MYFUTURE.FINISHED

MYFUTURE(STATUS)

MYFUTURE.ONCOMPLETE

To denote a parameter that may be repeated, what should you place after type?

%

&

_

-

What is it called when a superclass has more than one subclasses in Scala?

MULTIMODE INHERITANCE

MULTILEVEL INHERITANCE

HIERARCHICAL INHERITANCE

POLYINHERITANCE

What clause should you use with try to force the execution of code, even in the case of an exception?

FORCE

THROW

FINALLY

CATCH

What is an advantage of an immutable object?

IMMUTABLE OBJECTS DO NOT REQUIRE ERROR HANDLING.

IMMUTABLE OBJECTS ARE THREADSAFE.

IMMUTABLE OBJECTS CAN BE USED IN CLASSES, MUTABLE OBJECTS CANNOT.

IMMUTABLE OBJECTS USE LESS MEMORY THAN THEIR MUTABLE COUNTERPARTS.

What does this code return? val x = 3; if (x > 2) x=4 else x=x*2

3

4

AN ERROR

6

What operator performs a bitwise AND?

&

||

AND

&&

What command is used to define a singleton object?

OBJECT

NEW SINGLETON

NEW OBJECT

SINGLETON

One way to improve code reliability is to use _____, which will evaluate a condition and return an error if the condition is violated.?

TRAITS

POLYMORPHISMS

ASSERTIONS

PACKAGES

Which term makes the contents of packages available without prefixing?

ASSERTION

INCLUDE

USE

IMPORT

What value does this code return? x = List(1,2,4); x(1)?

NIL

(1,2,4)

2

1

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Exam Type:	Scala MCQ Skill Test
Questions Type:	Multiple Choice Questions
Total Questions:	30
Time Limit:	30 Minutes
Last Update	June, 2025

Pass Scala Exam

Scala Quiz

Scala bytecode can run on top of Java VM. What is the fundamental difference between Java object.clone() and Scala object.copy()?

What is one way to avoid low-level parallelization details?

What do you use in ScalaTest to see a detailed diagram of error messages when a test fails?

What data type would you use to store an immutable collection of objects that contain a fixed number of varying types?

After defining a function in the interpreter, Scala returns the following. What does the () indicate? myfnc: ()Unit

What type of number is 1234.e5?

When you convert a map to a list using the toList method of the map, the result will be of which type?

What type of object does this code create? val x = (1234, "Active")

Which is a subclass of all classes?

For the for-yield construct, is the scope separate between for-body and yield-body?

What is one way to implement pattern matching on methods?

What term is used to specify a precondition?

Which Scala type may throw an exception or a successfully computed value, and is commonly used to trap and propagate errors?

What is the data type of y after this code is executed? val y = (math floor 3.1415 * 2)

When using pattern matching, which character matches on any object?

You have created an array using val. Can you change the value of any element of the array—and why or why not?

What do you call objects with immutable state?

You have written a Scala script. How would you access command-line arguments in the script?

What does this code return? val x = 3; if (x >2) x = 4 else x = x*2

Which statement returns a success or failure indicator when you execute this code? val myFuture = Future {runBackgroundFunction() }

To denote a parameter that may be repeated, what should you place after type?

What is it called when a superclass has more than one subclasses in Scala?

What clause should you use with try to force the execution of code, even in the case of an exception?

What is an advantage of an immutable object?

What does this code return? val x = 3; if (x > 2) x=4 else x=x*2

What operator performs a bitwise AND?

What command is used to define a singleton object?

One way to improve code reliability is to use _____, which will evaluate a condition and return an error if the condition is violated.?

Which term makes the contents of packages available without prefixing?

What value does this code return? x = List(1,2,4); x(1)?

Scala Test Explained