Scjp 5 Study Guide Ch. 3

Front 1

local variables live on the ___

Back 1

stack

Front 2

objects and their instance variables live on the ___

Back 2

heap

Front 3

integer literals can be ___, ___, or ___

Back 3

decimal, octal (e.g. 013), or hexadecimal (e.g. 0x3d)

Front 4

literals for longs end in _ or _

Back 4

L, l

Front 5

float literals end in _, or _

Back 5

F, f

Front 6

double literals end in a ___ or _ or _

Back 6

digit, D, d

Front 7

the boolean literals are ___ and ___

Back 7

true, false

Front 8

literals for ___ are a single character inside single quotes: 'd'

Back 8

char

Front 9

___ refers to the lifetime of a variable

Back 9

scope

Front 10

static variables live basically as long as their ___ lives

Back 10

class

Front 11

instance variables live as long as their ___ lives

Back 11

object

Front 12

local variables live as long as their ___

Back 12

variable is on the stack; however, if their method invokes another method, they are temporarily unavailable

Front 13

block variables (e.g., in a for or an if) live until ___

Back 13

the block completes

Front 14

literal integers are implicitly ___

Back 14

ints

Front 15

integer expressions always result in an ___-sized result, never smaller

Back 15

int

Front 16

local variables live on the ___

Back 16

stack

Front 17

objects and their instance variables live on the ___

Back 17

heap

Front 18

integer literals can be ___, ___, or ___

Back 18

decimal, octal (e.g. 013), or hexadecimal (e.g. 0x3d)

Front 19

literals for longs end in _ or _

Back 19

L, l

Front 20

float literals end in _, or _

Back 20

F, f

Front 21

double literals end in a ___ or _ or _

Back 21

digit, D, d

Front 22

the boolean literals are ___ and ___

Back 22

true, false

Front 23

literals for ___ are a single character inside single quotes: 'd'

Back 23

char

Front 24

___ refers to the lifetime of a variable

Back 24

scope

Front 25

static variables live basically as long as their ___ lives

Back 25

class

Front 26

instance variables live as long as their ___ lives

Back 26

object

Front 27

local variables live as long as their ___

Back 27

variable is on the stack; however, if their method invokes another method, they are temporarily unavailable

Front 28

block variables (e.g., in a for or an if) live until ___

Back 28

the block completes

Front 29

literal integers are implicitly ___

Back 29

ints

Front 30

integer expressions always result in an ___-sized result, never smaller

Back 30

int

Front 31

floating point numbers are implicitly ___

Back 31

doubles (64-bit)

Front 32

narrowing a primitive truncates the ___ ___ bits

Back 32

high order

Front 33

compound assignments (e.g. +=) perform an ___ cast

Back 33

automatic

Front 34

a reference variable holds the bits that are used to ___

Back 34

refer to an object

Front 35

reference variables can refer to subclasses of the declared type but not to ___

Back 35

superclasses

Front 36

when creating a new object, e.g., Button b = new Button();, three things happen

Back 36

make a reference variable named b of type Button
create a new Button object
assign the Button object to the reference variable b

Front 37

when an array of objects is instantiated, objects within the array are not instantiated automatically, but all the references get the default value of ___

Back 37

null

Front 38

when an array of primitives is instantiated, elements get ___ ___

Back 38

default values

Front 39

instance variables are always initialized with ___

Back 39

a default value

Front 40

___ variables are never given a default value. if you attempt to use one before initializing it, you'll get a compiler error

Back 40

local/automatic/method

Front 41

methods can take ___ and/or ___ ___ as arguments

Back 41

primitives, object references

Front 42

method arguments are always ___

Back 42

copies

Front 43

a primitive argument is an ___ ___ of the original primitive

Back 43

unattached copy

Front 44

a reference argument is ___

Back 44

a copy of a reference to the original object

Front 45

___ occurs when two variables with different scopes share the same name. this leads to hard-to-find bugs and hard-to-answer exam questions

Back 45

shadowing

Front 46

arrays can hold primitives or objects, but the array itself is always an ___

Back 46

object

Front 47

when you declare an array, the brackets ___

Back 47

can be left or right of the name

Front 48

it is never legal to include the ___ of an array in the declaration

Back 48

size

Front 49

you must include the size of an array when you construct it (using new) unless you ___

Back 49

are creating an anonymous array

Front 50

elements in an array of objects are ___, although primitive array elements are given default values

Back 50

not automatically created

Front 51

you'll get a ___ if you try to use an array element in an object array, if that element does not refer to a real object

Back 51

NullPointerException

Front 52

arrays are indexed beginning with ___

Back 52

zero

Front 53

an ___ occurs if you use a bad index value

Back 53

ArrayIndexOutOfBoundsException

Front 54

arrays have a length variable whose value is ___

Back 54

the number of array elements

Front 55

the last index you can access is always ___ of the array

Back 55

one less than the length

Front 56

multidimensional arrays are just ___

Back 56

arrays of arrays

Front 57

the dimensions in a multidimensional array can/cannot have different lengths

Back 57

can

Front 58

an array of ___ can accept any value that can be promoted implicitly to the array's declared type:. e.g., a byte variable can go in an int array

Back 58

primitives

Front 59

an array of objects can hold any object that passes the ___ test for the declared type of the array. for example, if Horse extends Animal, then a Horse object can go into an Animal array

Back 59

IS-A (or instanceof)

Front 60

if you assign an array to a previously declared array reference, the array you're assigning ___

Back 60

must be the same dimension as the reference you're assigning it to.

Front 61

you can assign an array of one type to a previously declared array reference of one of its ___. for example, a Honda array can be assigned to an array declared as type Car (assuming Honda extends Car)

Back 61

supertypes

Front 62

static initialization blocks run ___, when the class is first loaded

Back 62

once

Front 63

instance initialization blocks run ___. they run after all super-constructors and before the constructor's code has run

Back 63

every time a new instance is created

Front 64

if multiple init blocks exist in a class, ___

Back 64

they follow the other rules of init blocks, AND they run in the order in which they appear in the source file

Front 65

the wrapper classes correlate to the ___ types

Back 65

primitive

Front 66

wrappers have two main functions

Back 66

to wrap primitives so that they can be handled like objects
to provide utility methods for primitives (usually conversions)

Front 67

the three most important method families are

Back 67

xxxValue() takes no arguments, returns primitive
parseXxx() takes String, returns primitive, throws NFE
valueOf() takes String, returns wrapped object, throws NFE

Front 68

wrapper constructors can take a String or a primitive, except for ___

Back 68

Character, which can only take a char

Front 69

radix refers to ___

Back 69

bases (typically) other than 10; octal is radix = 8, hex = 16

Front 70

___ allows you to convert primitives to wrappers or to convert wrappers to primitives automatically

Back 70

boxing

Front 71

using ___ with wrappers created through autoboxing is tricky

Back 71

==, those with small values (typically lower than 127), will be ==, larger values will not be ==

Front 72

___ ___ uses the "smallest" method argument possible

Back 72

primitive widening

Front 73

used individually, boxing and var-args are compatible with ___

Back 73

overloading

Front 74

you ___ widen from one wrapper type to another

Back 74

CANNOT, IS-A fails

Front 75

you ___ widen and then box

Back 75

CANNOT, an int can't become a long

Front 76

you can assign an array of one type to a previously declared array reference of one of its ___. for example, a Honda array can be assigned to an array declared as type Car (assuming Honda extends Car)

Back 76

supertypes

Front 77

static initialization blocks run ___, when the class is first loaded

Back 77

once

Front 78

instance initialization blocks run ___. they run after all super-constructors and before the constructor's code has run

Back 78

every time a new instance is created

Front 79

if multiple init blocks exist in a class, ___

Back 79

they follow the other rules of init blocks, AND they run in the order in which they appear in the source file

Front 80

the wrapper classes correlate to the ___ types

Back 80

primitive

Front 81

wrappers have two main functions

Back 81

to wrap primitives so that they can be handled like objects
to provide utility methods for primitives (usually conversions)

Front 82

the three most important method families are

Back 82

xxxValue() takes no arguments, returns primitive
parseXxx() takes String, returns primitive, throws NFE
valueOf() takes String, returns wrapped object, throws NFE

Front 83

wrapper constructors can take a String or a primitive, except for ___

Back 83

Character, which can only take a char

Front 84

radix refers to ___

Back 84

bases (typically) other than 10; octal is radix = 8, hex = 16

Front 85

___ allows you to convert primitives to wrappers or to convert wrappers to primitives automatically

Back 85

boxing

Front 86

using ___ with wrappers created through autoboxing is tricky

Back 86

==, those with small values (typically lower than 127), will be ==, larger values will not be ==

Front 87

___ ___ uses the "smallest" method argument possible

Back 87

primitive widening

Front 88

used individually, boxing and var-args are compatible with ___

Back 88

overloading

Front 89

you ___ widen from one wrapper type to another

Back 89

CANNOT, IS-A fails

Front 90

you ___ widen and then box

Back 90

CANNOT, an int can't become a Long

Front 91

you ___ box and then widen

Back 91

can, (an int can become an Object, via an Integer)

Front 92

you can combine ___ with either widening or boxing

Back 92

var-args

Front 93

in Java, ___ provides automated memory management

Back 93

garbage collection (GC)

Front 94

the purpose of GC is ___

Back 94

to delete objects that can't be reached

Front 95

___ ___ ___ decides when to run the GC

Back 95

only the JVM, you can only suggest it

Front 96

you can't know the ___ ___ for sure

Back 96

GC algorithm

Front 97

objects must be considered ___ before they can be garbage collected

Back 97

eligible

Front 98

an object is ___ when no live thread can reach it

Back 98

eligible

Front 99

to reach an object, you must have a ___

Back 99

live, reachable reference to that object

Front 100

Java applications can/can't run out of memory

Back 100

can

Front 101

islands of objects can/can't be GCed

Back 101

can, even though they refer to each other

Front 102

request garbage collection with ___

Back 102

System.gc(); (recommended)

Front 103

class ___ has a finalize() method

Back 103

Object

Front 104

the ___ method is guaranteed to run once and only once before the garbage collector deletes an object

Back 104

finalize()

Front 105

the garbage collector makes no guarantees

Back 105

finalize() may never run

Front 106

you can make an object ineligible for GC from within ___

Back 106

finalize()