Java Keywords

Question 1

abstract

Answer 1

A non-access modifier. Used for classes and methods: An abstract class cannot be used to create objects (to access it, it must be inherited from another class). An abstract method can only be used in an abstract class, and it does not have a body. The body is provided by the subclass (inherited from)

Question 2

assert

Answer 2

For debugging

Question 3

boolean

Answer 3

A data type that can only store true and false values

Question 4

break

Answer 4

Breaks out of a loop or a switch block

Question 5

byte

Answer 5

A data type that can store whole numbers from -128 and 127

Question 6

case

Answer 6

Marks a block of code in switch statements

Question 7

catch

Answer 7

Catches exceptions generated by try statements

Question 8

char

Answer 8

A data type that is used to store a single character

Question 9

class

Answer 9

Defines a class

Question 10

continue

Answer 10

Continues to the next iteration of a loop

Question 11

default

Answer 11

Specifies the default block of code in a switch statement

Question 12

do

Answer 12

Used together with while to create a do-while loop

Question 13

double

Answer 13

A data type that can store whole numbers from 1.7e−308 to 1.7e+308

Question 14

else

Answer 14

Used in conditional statements to specify a new condition if the first condition is false

Question 15

enum

Answer 15

Declares an enumerated (unchangeable) type

Question 16

exports

Answer 16

Exports a package with a module. New in Java 9

Question 17

extends

Answer 17

Extends a class (indicates that a class is inherited from another class)

Question 18

final

Answer 18

A non-access modifier used for classes, attributes and methods, which makes them non-changeable (impossible to inherit or override)

Question 19

finally

Answer 19

Used with exceptions, a block of code that will be executed no matter if there is an exception or not

Question 20

float

Answer 20

A data type that can store whole numbers from 3.4e−038 to 3.4e+038

Question 20

for

Answer 20

Create a for loop

Question 21

if

Answer 21

Makes a conditional statement

Question 21

implements

Question 21

import

Answer 21

Used to import a package, class or interface

Question 22

instanceof

Answer 22

Checks whether an object is an instance of a specific class or an interface

Question 23

interface

Answer 23

Used to declare a special type of class that only contains abstract methods

Question 23

int

Answer 23

A data type that can store whole numbers from -2147483648 to 2147483647

Question 24

long

Answer 24

A data type that can store whole numbers from -9223372036854775808 to 9223372036854775808

Question 25

module

Answer 25

Declares a module. New in Java 9

Question 26

native

Answer 26

Specifies that a method is not implemented in the same Java source file (but in another language)

Question 27

new

Answer 27

Creates new objects

Question 28

package

Answer 28

Declares a package

Question 29

private

Answer 29

An access modifier used for attributes, methods and constructors, making them only accessible within the declared class

Question 30

protected

Answer 30

An access modifier used for attributes, methods and constructors, making them accessible in the same package and subclasses

Question 31

public

Answer 31

An access modifier used for classes, attributes, methods and constructors, making them accessible by any other class

Question 32

requires

Answer 32

Specifies required libraries inside a module. New in Java 9

Question 33

return

Answer 33

Finished the execution of a method, and can be used to return a value from a method

Question 33

short

Answer 33

A data type that can store whole numbers from -32768 to 32767

Question 33

static

Answer 33

A non-access modifier used for methods and attributes. Static methods/attributes can be accessed without creating an object of a class

Question 33

strictfp

Answer 33

Restrict the precision and rounding of floating point calculations

Question 33

switch

Answer 33

Selects one of many code blocks to be executed

Question 33

super

Answer 33

Refers to superclass (parent) objects

Question 33

synchronized

Answer 33

A non-access modifier, which specifies that methods can only be accessed by one thread at a time

Question 33

this

Answer 33

Refers to the current object in a method or constructor

Question 34

throw

Answer 34

Creates a custom error

Question 34

throws

Answer 34

Indicates what exceptions may be thrown by a method

Question 34

transient

Answer 34

A non-accesss modifier, which specifies that an attribute is not part of an object’s persistent state

Question 34

try

Answer 34

Creates a try…catch statement

Question 34

var

Answer 34

Declares a variable. New in Java 10

Question 34

void

Answer 34

Specifies that a method should not have a return value

Question 34

volatile

Answer 34

Indicates that an attribute is not cached thread-locally, and is always read from the “main memory”

Question 34

while

Answer 34

Creates a while loop

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

int

Answer 34

A data type that can store whole numbers from -2147483648 to 2147483647

Question 34

try

Answer 34

Creates a try…catch statement

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

int

Answer 34

A data type that can store whole numbers from -2147483648 to 2147483647

Question 34

instanceof

Answer 34

Checks whether an object is an instance of a specific class or an interface

Question 34

float

Answer 34

A data type that can store whole numbers from 3.4e−038 to 3.4e+038

Question 34

try

Answer 34

Creates a try…catch statement

Question 34

int

Answer 34

A data type that can store whole numbers from -2147483648 to 2147483647

Question 34

try

Answer 34

Creates a try…catch statement

Question 34

float

Answer 34

A data type that can store whole numbers from 3.4e−038 to 3.4e+038

Question 34

instanceof

Answer 34

Checks whether an object is an instance of a specific class or an interface

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

instanceof

Answer 34

Checks whether an object is an instance of a specific class or an interface

Question 34

int

Answer 34

A data type that can store whole numbers from -2147483648 to 2147483647

Question 34

try

Answer 34

Creates a try…catch statement

Question 34

static

Answer 34

A non-access modifier used for methods and attributes. Static methods/attributes can be accessed without creating an object of a class

Question 34

float

Answer 34

A data type that can store whole numbers from 3.4e−038 to 3.4e+038

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

instanceof

Answer 34

Checks whether an object is an instance of a specific class or an interface

Question 34

this

Answer 34

Refers to the current object in a method or constructor

Question 34

int

Answer 34

A data type that can store whole numbers from -2147483648 to 2147483647

Question 34

float

Answer 34

A data type that can store whole numbers from 3.4e−038 to 3.4e+038