1671 + Mcqs in Java Page 9 McqOptions

401.	Which statement is true given the following?Double d = Math.random();
A.	0.0 < d <= 1.0
B.	0.0 <= d < 1.0
C.	Compilation fail
D.	Cannot say.
Answer» C. Compilation fail

Discussion

402.	Which two statements are true about wrapper or String classes?1. If x and y refer to instances of different wrapper classes, then the fragment x.equals(y) will cause a compiler failure.2. If x and y refer to instances of different wrapper classes, then x == y can sometimes be true.3. If x and y are String references and if x.equals(y) is true, then x == y is true.4. If x, y, and z refer to instances of wrapper classes and x.equals(y) is true, and y.equals(z) is true, then z.equals(x) will always be true.5. If x and y are String references and x == y is true, then y.equals(x) will be true.
A.	1 and 2
B.	2 and 3
C.	3 and 4
D.	4 and 5
Answer» E.

Discussion

403.	Which of these class have only one field "TYPE"?
A.	Void
B.	Process
C.	System
D.	Runtime
Answer» B. Process

Discussion

404.	Standard output variable "out" is defined in which class?
A.	Void
B.	Process
C.	Runtime
D.	System
Answer» E.

Discussion

405.	What is the value of “d” after this line of code has been executed? double d = Math.round ( 2.5 + Math.random() );
A.	2
B.	3
C.	4
D.	2.5
Answer» C. 4

Discussion

406.	What is the output of this program?Note: inputoutput.java is stored in the disk.
A.	true
B.	false
C.	prints number of bytes in file
D.	prints number of characters in the file
Answer» D. prints number of characters in the file

Discussion

407.	Ethernet frame consists of:
A.	MAC address
B.	IP address
C.	both (a) and (b)
D.	none of the mentioned
Answer» B. IP address

Discussion

408.	What are the main methods of Java Regex?
A.	matches
B.	lookingAt
C.	find
D.	All of the above
Answer» E.

Discussion

409.	Which of the following statements about the regex API are true?
A.	Instances of the Pattern class are used to match character sequences against a given pattern
B.	The package java.util.regex includes an exception called PatternSyntaxException
C.	Instances of Matcher class are used to represent regular expressions in the form of String type
D.	None of the above
Answer» C. Instances of Matcher class are used to represent regular expressions in the form of String type

Discussion

410.	What does public int start() return?
A.	returns start index of the input string
B.	returns start index of the current match
C.	returns start index of the previous match
D.	none of the mentioned
Answer» D. none of the mentioned

Discussion

411.	The set of all strings over Sigma = {a,b} in which all strings having bbbb as substring is
A.	(a+b)* bbbb (a+b)*
B.	(a+b)* bb (a+b)*bb
C.	bbbb (a+b)*
D.	bb (a+b)*
Answer» B. (a+b)* bb (a+b)*bb

Discussion

412.	Regular expressions are used to represent which language
A.	Recursive language
B.	Context free language
C.	Regular language
D.	All of these
Answer» D. All of these

Discussion

413.	Which of the following is not a class of java.util.regex?
A.	Pattern class
B.	matcher class
C.	PatternSyntaxException
D.	Regex class
Answer» E.

Discussion

414.	Which of the following identity is wrong?
A.	R + R = R
B.	R) = R*
C.	Both A and B
D.	(phi)R = R(phi) = RR*
Answer» E.

Discussion

415.	What does public int end(int group) return?
A.	offset from last character of the subsequent group
B.	offset from first character of the subsequent group
C.	offset from last character matched
D.	offset from first character matched
Answer» B. offset from first character of the subsequent group

Discussion

416.	Which capturing group can represent the entire expression?
A.	group *
B.	group 0
C.	group * or group 0
D.	None of the mentioned
Answer» C. group * or group 0

Discussion

417.	What is the significance of Matcher class for regular expression in java?
A.	interpretes pattern in the string
B.	Performs match in the string
C.	interpretest both pattern and performs match operations in the string
D.	None of the mentioned
Answer» D. None of the mentioned

Discussion

418.	Which of these instances cannot be created?
A.	Integer Instance
B.	Generic Class Instance
C.	Generic Type Instance
D.	Collection Instances
Answer» D. Collection Instances

Discussion

419.	Which of these types cannot be used to initiate a generic type?
A.	Integer class
B.	Float Class
C.	Primitive Types
D.	Collections
Answer» D. Collections

Discussion

420.	What is the default value of byte variable?
A.	0
B.	0.5
C.	nul
D.	undefined
Answer» B. 0.5

Discussion

421.	Which of the following reference types cannot be generic?
A.	Anonymous inner class
B.	Interface
C.	Inner class
D.	All of the mentioned
Answer» B. Interface

Discussion

422.	Which of the following is Faster, StringBuilder or StringBuffer?
A.	StringBuilder
B.	StringBuffer
C.	Both of the above
D.	None of the above
Answer» B. StringBuffer

Discussion

423.	Why are generics used?
A.	Generics make code more fast
B.	Generics make code more optimised and readable
C.	Generics add stability to your code by making more of your bugs detectable at compile time
D.	Generics add stability to your code by making more of your bugs detectable at a runtime
Answer» D. Generics add stability to your code by making more of your bugs detectable at a runtime

Discussion

424.	Which of the following allows us to call generic methods as a normal method?
A.	Type Interface
B.	Interface
C.	Inner class
D.	All of the mentioned
Answer» B. Interface

Discussion

425.	Which of the following is incorrect statement regarding the use of generics and parameterized types in Java?
A.	Generics provide type safety by shifting more type checking responsibilities to the compiler
B.	Generics and parameterized types eliminate the need for down casts when using Java Collections
C.	When designing your own collections class (say, a linked list), generics and parameterized types allow you to achieve type safety with just a single class definition as opposed to defining multiple classes
D.	All of the mentioned
Answer» D. All of the mentioned

Discussion

426.	Which of these type parameters is used for a generic class to return and accept a number?
A.	K
B.	N
C.	T
D.	V
Answer» C. T

Discussion

427.	Functional interfaces can be annotated as
A.	Function
B.	FunctionalInterface
C.	Functional
D.	Interface
Answer» C. Functional

Discussion

428.	Given a class named student, which of the following is a valid constructor declaration for the class?
A.	Student (student s) { }
B.	Student student ( ) { }
C.	Private final student ( ) { }
D.	Void student ( ) { }
Answer» B. Student student ( ) { }

Discussion

429.	Which of the following are not valid lambda expressions?
A.	() -> {}
B.	() -> “Raoul”
C.	() -> {return “Mario”;}
D.	(Integer i) -> return “Alan” + i;
Answer» E.

Discussion

430.	Which of these does Stream map() operates on
A.	Class
B.	Interface
C.	Predicate
D.	Function
Answer» E.

Discussion

431.	A functional interface acts as target types for which of the following?
A.	Lambda expression
B.	Method reference
C.	Constructor reference
D.	All of the above
Answer» E.

Discussion

432.	Which statement is true regarding an object?
A.	An object is what classes instantiated are from
B.	An object is an instance of a class
C.	An object is a variable
D.	An object is a reference to an attribute
Answer» C. An object is a variable

Discussion

433.	What is the return type of lambda expression?
A.	String
B.	Object
C.	void
D.	Function
Answer» E.

Discussion

434.	If a variable is declared final, it must include …………………. value.
A.	integer
B.	no
C.	initial
D.	float
Answer» D. float

Discussion

435.	Which is aggregate operation in Java 8
A.	filter
B.	map
C.	forEach
D.	All
Answer» B. map

Discussion

436.	Example of functional interfaces
A.	java.util.concurrent.Callable
B.	java.lang.Runnable
C.	All
D.	None
Answer» D. None

Discussion

437.	Using which keyword we can access a value of the instance variables and class variables of that class inside the method of that class itself.
A.	Super
B.	Final
C.	This
D.	Either super or this
Answer» D. Either super or this

Discussion

438.	Which of the following does not belong: If a class inherits from some other class, it should
A.	Make use of the parent class’s capabilities
B.	Over-ride or add the minimum to accomplish the derived class’ purpose
C.	Over-ride all the methods of its parent class
D.	Make sure the result “IS-A-KIND-OF” its base class
Answer» D. Make sure the result “IS-A-KIND-OF” its base class

Discussion

439.	PermGen space has been replaced with which of these in Java 8
A.	PermSpace
B.	PermSpaceGen
C.	Metaspace
D.	MetaGenSpace
Answer» D. MetaGenSpace

Discussion

440.	How many methods are there in a functional interface in Java 8?
A.	0
B.	1
C.	2
D.	3
Answer» C. 2

Discussion

441.	What is the Optional object used for?
A.	Optional is used for optional runtime argument
B.	Optional is used for optional spring profile
C.	Optional is used to represent null with absent value
D.	Optional means its not mandatory for method to return object
Answer» D. Optional means its not mandatory for method to return object

Discussion

442.	Which of the following gets introduced with Java 8?
A.	Lambda expression
B.	Compact profiles
C.	Stream API
D.	Only first two
Answer» B. Compact profiles

Discussion

443.	A method within a class is only accessible by classes that are defined within the same package as the class of the method. Which one of the following is used to enforce such restriction?
A.	Declare the method with the keyword public
B.	Declare the method with the keyword private
C.	Declare the method with the keyword protected
D.	Do not declare the method with any accessibility modifiers
Answer» E.

Discussion

444.	In Java 8 Interfaces, methods can be:
A.	default
B.	abstract
C.	all
D.	None
Answer» D. None

Discussion

445.	The newly introduced Streams API is available in which package of java 8:
A.	java.io.streams
B.	java.io.stream
C.	java.util.streams
D.	java.util.stream
Answer» E.

Discussion

446.	A pipeline is a sequence of what operations in java 8
A.	multi-threading
B.	concurrent
C.	consequent
D.	stream
Answer» E.

Discussion

447.	What does SAM stand for in context of Functional Interface?
A.	Single Ambivalue Method
B.	Single Abstract Method
C.	Simple Active Markup
D.	Simple Abstract Markup
Answer» C. Simple Active Markup

Discussion

448.	Code for Java 8 essentially used to be
A.	Declarative
B.	Imperative
C.	Subjective
D.	None
Answer» C. Subjective

Discussion

449.	Nashorn the new JavaScript engine is an implementation of
A.	javax.engine.Engine
B.	javax.script.Engine
C.	javax.javaScript.Engine
D.	javax.script.ScriptEngine
Answer» E.

Discussion

450.	Which of the following functional interface represents a function that accepts a double-valued argument and produces a long-valued result?
A.	DoubleToLongFunction
B.	DoubleUnaryOperator
C.	Function
D.	IntBinaryOperator
Answer» B. DoubleUnaryOperator

Discussion

Explore topic-wise MCQs in Technical Programming.

Which statement is true given the following?Double d = Math.random();

Which of these class have only one field "TYPE"?

Standard output variable "out" is defined in which class?

What is the value of “d” after this line of code has been executed? double d = Math.round ( 2.5 + Math.random() );

What is the output of this program?Note: inputoutput.java is stored in the disk.

Ethernet&nbsp;frame&nbsp;consists&nbsp;of:

What&nbsp;are&nbsp;the&nbsp;main&nbsp;methods&nbsp;of&nbsp;Java&nbsp;Regex?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;statements&nbsp;about&nbsp;the&nbsp;regex&nbsp;API&nbsp;are&nbsp;true?

What&nbsp;does&nbsp;public&nbsp;int&nbsp;start()&nbsp;return?

The&nbsp;set&nbsp;of&nbsp;all&nbsp;strings&nbsp;over&nbsp;Sigma&nbsp;=&nbsp;{a,b}&nbsp;in&nbsp;which&nbsp;all&nbsp;strings&nbsp;having&nbsp;bbbb&nbsp;as&nbsp;substring&nbsp;is

Regular&nbsp;expressions&nbsp;are&nbsp;used&nbsp;to&nbsp;represent&nbsp;which&nbsp;language

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;is&nbsp;not&nbsp;a&nbsp;class&nbsp;of&nbsp;java.util.regex?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;identity&nbsp;is&nbsp;wrong?

What&nbsp;does&nbsp;public&nbsp;int&nbsp;end(int&nbsp;group)&nbsp;return?

Which&nbsp;capturing&nbsp;group&nbsp;can&nbsp;represent&nbsp;the&nbsp;entire&nbsp;expression?

What&nbsp;is&nbsp;the&nbsp;significance&nbsp;of&nbsp;Matcher&nbsp;class&nbsp;for&nbsp;regular&nbsp;expression&nbsp;in&nbsp;java?

Which&nbsp;of&nbsp;these&nbsp;instances&nbsp;cannot&nbsp;be&nbsp;created?

Which&nbsp;of&nbsp;these&nbsp;types&nbsp;cannot&nbsp;be&nbsp;used&nbsp;to&nbsp;initiate&nbsp;a&nbsp;generic&nbsp;type?

What&nbsp;is&nbsp;the&nbsp;default&nbsp;value&nbsp;of&nbsp;byte&nbsp;variable?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;reference&nbsp;types&nbsp;cannot&nbsp;be&nbsp;generic?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;is&nbsp;Faster,&nbsp;StringBuilder&nbsp;or&nbsp;StringBuffer?

Why&nbsp;are&nbsp;generics&nbsp;used?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;allows&nbsp;us&nbsp;to&nbsp;call&nbsp;generic&nbsp;methods&nbsp;as&nbsp;a&nbsp;normal&nbsp;method?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;is&nbsp;incorrect&nbsp;statement&nbsp;regarding&nbsp;the&nbsp;use&nbsp;of&nbsp;generics&nbsp;and&nbsp;parameterized&nbsp;types&nbsp;in&nbsp;Java?

Which&nbsp;of&nbsp;these&nbsp;type&nbsp;parameters&nbsp;is&nbsp;used&nbsp;for&nbsp;a&nbsp;generic&nbsp;class&nbsp;to&nbsp;return&nbsp;and&nbsp;accept&nbsp;a&nbsp;number?

Functional&nbsp;interfaces&nbsp;can&nbsp;be&nbsp;annotated&nbsp;as

Given&nbsp;a&nbsp;class&nbsp;named&nbsp;student,&nbsp;which&nbsp;of&nbsp;the&nbsp;following&nbsp;is&nbsp;a&nbsp;valid&nbsp;constructor&nbsp;declaration&nbsp;for&nbsp;the&nbsp;class?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;are&nbsp;not&nbsp;valid&nbsp;lambda&nbsp;expressions?

Which&nbsp;of&nbsp;these&nbsp;does&nbsp;Stream&nbsp;map()&nbsp;operates&nbsp;on

A&nbsp;functional&nbsp;interface&nbsp;acts&nbsp;as&nbsp;target&nbsp;types&nbsp;for&nbsp;which&nbsp;of&nbsp;the&nbsp;following?

Which&nbsp;statement&nbsp;is&nbsp;true&nbsp;regarding&nbsp;an&nbsp;object?

What&nbsp;is&nbsp;the&nbsp;return&nbsp;type&nbsp;of&nbsp;lambda&nbsp;expression?

&nbsp;If&nbsp;a&nbsp;variable&nbsp;is&nbsp;declared&nbsp;final,&nbsp;it&nbsp;must&nbsp;include&nbsp;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;.&nbsp;value.

Which&nbsp;is&nbsp;aggregate&nbsp;operation&nbsp;in&nbsp;Java&nbsp;8

Example&nbsp;of&nbsp;functional&nbsp;interfaces

Using&nbsp;which&nbsp;keyword&nbsp;we&nbsp;can&nbsp;access&nbsp;a&nbsp;value&nbsp;of&nbsp;the&nbsp;instance&nbsp;variables&nbsp;and&nbsp;class&nbsp;variables&nbsp;of&nbsp;that&nbsp;class&nbsp;inside&nbsp;the&nbsp;method&nbsp;of&nbsp;that&nbsp;class&nbsp;itself.

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;does&nbsp;not&nbsp;belong:&nbsp;If&nbsp;a&nbsp;class&nbsp;inherits&nbsp;from&nbsp;some&nbsp;other&nbsp;class,&nbsp;it&nbsp;should

PermGen&nbsp;space&nbsp;has&nbsp;been&nbsp;replaced&nbsp;with&nbsp;which&nbsp;of&nbsp;these&nbsp;in&nbsp;Java&nbsp;8

How&nbsp;many&nbsp;methods&nbsp;are&nbsp;there&nbsp;in&nbsp;a&nbsp;functional&nbsp;interface&nbsp;in&nbsp;Java&nbsp;8?

What&nbsp;is&nbsp;the&nbsp;Optional&nbsp;object&nbsp;used&nbsp;for?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;gets&nbsp;introduced&nbsp;with&nbsp;Java&nbsp;8?

In&nbsp;Java&nbsp;8&nbsp;Interfaces,&nbsp;methods&nbsp;can&nbsp;be:

The&nbsp;newly&nbsp;introduced&nbsp;Streams&nbsp;API&nbsp;is&nbsp;available&nbsp;in&nbsp;which&nbsp;package&nbsp;of&nbsp;java&nbsp;8:

A&nbsp;pipeline&nbsp;is&nbsp;a&nbsp;sequence&nbsp;of&nbsp;what&nbsp;operations&nbsp;in&nbsp;java&nbsp;8

What&nbsp;does&nbsp;SAM&nbsp;stand&nbsp;for&nbsp;in&nbsp;context&nbsp;of&nbsp;Functional&nbsp;Interface?

Code&nbsp;for&nbsp;Java&nbsp;8&nbsp;essentially&nbsp;used&nbsp;to&nbsp;be

Nashorn&nbsp;the&nbsp;new&nbsp;JavaScript&nbsp;engine&nbsp;is&nbsp;an&nbsp;implementation&nbsp;of

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;functional&nbsp;interface&nbsp;represents&nbsp;a&nbsp;function&nbsp;that&nbsp;accepts&nbsp;a&nbsp;double-valued&nbsp;argument&nbsp;and&nbsp;produces&nbsp;a&nbsp;long-valued&nbsp;result?

Ethernet frame consists of:

What are the main methods of Java Regex?

Which of the following statements about the regex API are true?

What does public int start() return?

The set of all strings over Sigma = {a,b} in which all strings having bbbb as substring is

Regular expressions are used to represent which language

Which of the following is not a class of java.util.regex?

Which of the following identity is wrong?

What does public int end(int group) return?

Which capturing group can represent the entire expression?

What is the significance of Matcher class for regular expression in java?

Which of these instances cannot be created?

Which of these types cannot be used to initiate a generic type?

What is the default value of byte variable?

Which of the following reference types cannot be generic?

Which of the following is Faster, StringBuilder or StringBuffer?

Why are generics used?

Which of the following allows us to call generic methods as a normal method?

Which of the following is incorrect statement regarding the use of generics and parameterized types in Java?

Which of these type parameters is used for a generic class to return and accept a number?

Functional interfaces can be annotated as

Given a class named student, which of the following is a valid constructor declaration for the class?

Which of the following are not valid lambda expressions?

Which of these does Stream map() operates on

A functional interface acts as target types for which of the following?

Which statement is true regarding an object?

What is the return type of lambda expression?

If a variable is declared final, it must include …………………. value.

Which is aggregate operation in Java 8

Example of functional interfaces

Using which keyword we can access a value of the instance variables and class variables of that class inside the method of that class itself.

Which of the following does not belong: If a class inherits from some other class, it should

PermGen space has been replaced with which of these in Java 8

How many methods are there in a functional interface in Java 8?

What is the Optional object used for?

Which of the following gets introduced with Java 8?

In Java 8 Interfaces, methods can be:

The newly introduced Streams API is available in which package of java 8:

A pipeline is a sequence of what operations in java 8

What does SAM stand for in context of Functional Interface?

Code for Java 8 essentially used to be

Nashorn the new JavaScript engine is an implementation of

Which of the following functional interface represents a function that accepts a double-valued argument and produces a long-valued result?