INDEX
−− (decrement) operator, 302–303
− (subtraction) operator, 306
! (boolean invert) logical operator, 309–310
! = (not equal to) operator, 292
% (remainder) operator, 299
& (non-short-circuit AND) operator, 288, 308
&& (short-circuit AND) operator, 306, 308, 548
* (multiplication) operator, 308
* quantifier, 495
· (dot) metacharacter, 497
·java files, 791–792
/ (division) operator, 306
: (colons), 354
; (semicolons), 17, 41, 344–345, 675
? quantifier, 495
@argfiles command-line options, 791
(backslashes), 798
∧ (exclusive-OR [XOR]) logical operator, 288, 309–310, 553
∧ (regex carat) operator, 494
| (non-short-circuit OR) operator, 288, 308
| | (short-circuit OR) operator, 306, 308
+ (addition) operator, 288, 299, 307
+ quantifier, 495
++ (increment) operator, 302–303
+= (compound additive operator), 301
<? extends Animal> syntax, 618
<? super …> syntax, 619
<> (angle brackets), 600
<?> wildcard, 620
<E> placeholder, 622
<Integer> type, 602
<JButton> type, 608
<Object> type, 600
<X> type declaration, 629
= (assignment) operators
assigning one primitive variable to another, 198
floating-point numbers, 196
literals too large for variable,
primitive casting, 193–195
primitive variables, 191–193
reference variable, 198–200
variable scope, 200–202
= = (equals) operator, 245–246, 292–294, 544
A
absolute paths, 801–802
abstract keyword, 15
abstract methods, 41–45
access control
class access, 13
default access, 13–14, 32–34, 36–38
defined, 12
local variables, 38–39
modifiers, 24–26
private members, 29–32
protected members, 32–36
access modifiers
declaring class members
local variables and, 38–39
overview, 24–26
private, 29–32
protected, 32–36
public, 26–29
defined, 12
method-local inner class, 682
addAnimals( ) method, 616–617
addition (+) operator, 288, 299, 307
addJob( ) method, 754–755
AND operators
&& short-circuit, 306, 308, 548
angle brackets (< >), 600
animate( ) method, 102
anonymous arrays, 228–230
anonymous inner classes
argument-defined, 678–680
overview, 673–678
anotherObject object, 749
append( ) method, 440
applications, launching with java command, 793–796
appropriate use of assertions, 392–394
arg_index format string element, 507
args index, 796
arguments. See also var-args
anonymous inner classes defined by, 678–680
defined, 46
final, 41
just-in-time array, 229–230
using assertions to validate, 392–393
arithmetic operators
decrement, 302–303
increment, 302–303
overview, 298
remainder, 299
string concatenation, 299–301
ArrayIndexOutOfBoundsException subclass, 224, 368, 382
ArrayList class
basics, 567–568
Collection Interface Concrete Implementation, 565
List interface implementation, 562
mixing generic and non-generic collections, 601–607
of Strings, 596
arrays
constructing
anonymous, 228–230
multidimensional, 223
on one line, 226–228
one-dimensional, 221–222
overview, 220–221
declarations, 55–57, 219–220, 226–228
enhanced for loop for, 350–352
initialization blocks, 234–237
initializing
and constructing anonymous, 228–230
declaring, and constructing on one line, 226–228
elements in loop, 225–226
legal element assignments, 230
multidimensional, 233–234
of object references, 231–232
one-dimensional, 232–233
overview, 224–225
primitive, 230–231
reference assignments for one-dimensional, 232–234
instance variables, 206
length attribute, 437
as objects, 297
primitive, 230–231
returning values, 128
shortcut syntax, 226–228
use of brackets, 56
Arrays class
asList ( ) method, 579
collections, 576
converting to Lists, 579
key methods, 593
searching, 576–578
sort( ) method, 576
asList ( ) method, 579
assert statements, 386–389, 394
AssertionError subtype, 375, 381–382, 385, 393
assertions
appropriate use of, 392–394
disabling
at runtime, 390
selective, 390–391
enabling
compiling assertion-aware code, 388–389
identifiers versus keywords, 387–388
at runtime, 389
selective, 390–391
expression rules, 385–387
assignment (=) operators
assigning one primitive variable to another, 198
floating-point numbers, 196
literals too large for variable, 196–197
primitive casting, 193–195
primitive variables, 191–193
reference variable, 198–200
variable scope, 200–202
assignments. See also arrays; garbage collection; wrappers
assignment operators
assigning one primitive variable to another, 198
floating-point numbers, 196
literals too large for variable, 196–197
overview, 190–191
primitive casting, 193–195
primitive variables, 191–193
reference variable, 198–200
variable scope, 200–202
autoboxing
equals( ) method, 245–246
equals operator, 245–246
overview, 244–245
use of, 246–247
heap, 184–185
literal values for primitive types boolean, 189
character, 189–190
floating-point, 188–189
integer, 186–188
overview, 186
string, 190
local variables
array references, 210
assigning one reference variable to another, 210–213
object references, 209–210
overview, 207
primitives, 207–209
overloading
with boxing and var-args, 249–250
in combination with var-args, 253–254
overview, 247–249
when combining widening and boxing, 251–253
widening reference variables, 250–251
passing variables into methods
object reference variables, 213–214
overview, 213
pass-by-value semantics, 214–215
primitive variables, 215–218
stack, 184–185
uninitialized variables
array, 206
object reference, 203–206
overview, 203
primitive, 203–204
atomic operations, 733–735
autoboxing
with collections, 568
equals( ) method, 245–246
equals operator, 245–246
overloading
with var-args and, 249–250
when combining widening and, 252–253
overview, 244–245
in switch statements, 337
use of, 246–247
automatic variables, 207. See also local variables
B
backed collections
key methods, 593–595
overview, 589–591
using PriorityQueue class, 591–592
backslashes (), 798
bar( ) method, 215
behavior, 2. See also methods
binarySearch( ) method, 576
bitwise operators, 305
block variables, 201
blocked threads, 719–720
boolean add(element) interface method, 594
boolean containsKey(object key) interface method, 594
boolean contains(object) interface method, 594
boolean containsValue(object value) interface method, 594
boolean createNewFile( ) method, 446
boolean equals (Object obj) method, 543
boolean exists( ) method, 446
boolean hasNext( ) method, 580
boolean invert (!) logical operator, 309–310
Boolean wrapper, 239
booleans
arguments in backed collections, 590–591
assigning versus testing, 334
literals, 189
for loops, 346–347
and relational operators, 290–291
boxing
equals( ) method, 245–246
equals operator, 245–246
overloading
with var-args and, 249–250
when combining widening and, 252–253
overview, 244–245
in switch statements, 337
use of, 246–247
brackets, array, 56
branching, if-else, 329–332
break statements
labeled, 354–356
in switch blocks, 338–340
switch statements, 335
unlabeled, 353–354
use of, 352–353
BufferedReader class, 443
BufferedWriter class, 444
byte variables, 192
C
Calculator class, 754
Calendar class, 477–479
call stack
constructors on, 133
overloaded constructors on, 141
propagating uncaught exceptions, 362–363
unwinding, 367
camelCase format, 7–8
can't-be-overridden restriction, 40
carat (∧) operator, 494
case constants
default, 341–342
evaluation of, 338
legal expressions for, 335–338
casting
primitive, 193–195
reference variables, 116–119
catch keyword, 357–359
ceiling( ) method, 587
ceilingKey( ) method, 587
chained methods, 442
chaining
combining I/O classes, 449–452
constructors, 132–133
changeNum( ) method, 470
changeSize( ) method, 110
character literals, 189–190
characters, Unicode, 51, 189, 426–427
charAt( ) method, 435
ChatClient class, 663–664
checked exceptions, 373–375
checkup( ) method, 608
class literals, 738
ClassCastException class, 382, 547
classes. See also dates; exceptions; individual classes by name; inner classes; member declarations
collections, 557–561
combining, 449–452
declaration
abstract classes, 16–19
class access, 13
default access, 13–14
final classes, 15–16
overview, 10–11
public access, 13–15
source file rules, 11–12
defined, 2
finding other, 3–4
generic, 623–627
interfaces
implementing, 122
relationship with, 20
naming standards, 7
searching for
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801-802
thread-safe, 742–744
wrapper, 237–238
classes directory, 791–793
−classpath option, javac command, 790–791, 794, 798
close( ) method, 448–449
cmdProp=cmdVal property, 795
Collection classes, 56
Collection interface, 557–559
collections. See also generics; hashCode( ) method
ArrayList basics, 567–568
autoboxing with, 568
backed
key methods, 593–595
overview, 589–591
using PriorityQueue class, 591-592
classes, 557–561
converting arrays to Lists to arrays, 579
interfaces
List, 561–562
Map, 563–564
overview, 557–561
Queue, 564–566
Set, 562–563
legacy code, 597–600
Lists, 580–581
Maps, 583–586
mixing generic and non-generic, 601–607
overriding Object methods
equals( ), 544–549
overview, 542
toString( ), 542–544
overview, 556–557
searching
arrays and, 576–578
TreeSets and TreeMaps, 586–588
Sets, 581–583
sorting
Arrays class, 576
Comparable interface, 571–573
Comparator interface, 574–575
overview, 569–571
Collections class, 593
Collections Framework, 556
Collections.sort( ) method, 571, 573–574, 576
Collections.synchronizedList( ) method, 743–744
colons (:), 354
combining I/O classes, 449–452
command-line arguments, 393, 795–796
commands
jar, 803–804
java command, 793–796
javac
assertion-aware code, 388–389
compiling with, 790–793
constructor code generated by, 137
failures, 350
JAR files, 804
warnings, 603
searching for other classes with
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
Comparable interface, 561, 566, 571–573
Comparator interface, 561, 574–575, 592
compare( ) method, 574
compareTo( ) method, 571–574
compiler
assertion-aware code, 388–389
constructor code generated by, 137
failures, 350
JAR files, 804
javac command, 790–793
searching for other classes
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
warnings, 603
compound additive operator (+=), 301
compound assignment operators, 197, 289–290
concat( ) method, 435–436
concatenation operator, string, 299–301
concrete classes, 42–44
conditional expressions, 346–347
conditional operators, 304–305
consistency of equals( ) method, 549
constant pool, String, 434
constant specific class bodies, 63, 65
constants
case
default, 341–342
evaluation of, 338
legal expressions for, 335–338
declaring interface, 22–23
enums, 63
MAX_VALUE, 807
values, 23
constructing arrays, 220–223
constructor arguments, 238, 628
constructors
chaining, 132–133
code causing to run, 222
compiler-generated, 137
declarations
in enums, 63–65
overview, 47–48
default, 135–139
overloaded, 139–145
overview, 130–132
rules for, 133–134
super, 136–139
wrapper, 239
continue statements
labeled, 354–356
overview, 352–353
unlabeled, 353–354
contracts
equals( ) method, 549
hashCode( ) method, 554–556
conversion format string element, 508
conversion utilities, wrapper
parseXxx( ) methods, 241
toString( ) method, 242
toXxxString( ) method, 242–243
valueOf( ) method, 241
xxxValue( ) methods, 240–241
copying reference variables, 213
correct use of assertions, 392–394
coupling, 151–153
covariant returns, 127–128
−cp abbreviation, java command, 798
CreateAnArrayList class, 628
−d option, javac command, 790–793
−D option, system properties, 794–795
D
daemon threads, 704
DataInputStream class, 473
DataOutputStream class, 473
Date class, 476–477
DateFormat class, 480–481, 484
dates
Calendar class, 477–479
Date class, 476–477
DateFormat class, 480–481
Locale class, 482–485
orchestrating classes related to, 474–475
overview, 473–474
deadlocks, thread, 745–746
"Deadly Diamond of Death" scenario, 100
decimal literals, 186
decision statements
if
if-else branching, 329–332
legal expressions for, 332–334
overview, 328
switch
break statement in, 335, 338–340
default case, 341–342
fall-through in, 338–340
legal expressions for, 335–338
declaration
access modifiers
local variables and, 38–39
overview, 24–26
private, 29–32
protected, 32–36
public, 26–29
class
abstract, 16–19
access, 13
default access, 13–14
final, 15–16
overview, 10–11
public access, 13–15
source file rules, 11–12
classpath, 797–798
constructor, 47–48
enum
constructors, methods, and variables in, 63–65
overview, 60–63
exception, 371–376
generics
classes, 623–627
methods, 627–630
overview, 622–623
interface
constants, 22–23
overview, 19–22
nonaccess modifiers
abstract methods, 41–45
final arguments, 41
final methods, 40
methods with var-args, 46–47
native methods, 46
overview, 39
strictfp methods, 46
synchronized methods, 45
var-arg rule, 47
variable
array, 55–57
in enums, 63–65
final, 57–58
generics and polymorphism, 608
instance, 51–53
local, 53–55
overview, 49
primitive, 49–51
reference, 51
static, 59–60
transient, 59
volatile, 59
declared return types, 129
decoupling reference variables, 258
decrement (−−) operator, 302–303
default access classes, 13–14
default access control type, 24
default constructors, 135–139
default hashcode method, 552
default keyword, 341–343
default primitive and reference type values, 203
default priority, thread, 725
defining threads, 705–706
delete( ) method, 440–441
delimiters, 502
descending order, 588
development
compiling with javac command, 790–793
Java Archive files, 802–805
launching applications with java command, 793–796
overview, 789–790
searching for other classes
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
static imports, 806–807
direct subdirectories, 802
directories
classpaths, 797–798
javac command, 791–793
META-INF, 804
myApp, 803
relative and absolute paths, 801–802
root, 804
source, 792
working with files and, 452–457
disabling assertions
at runtime, 390
selective, 390–391
division (/) operator, 306
do loops, 344–345
doInsert( ) method, 620
doStuff( ) method, 114, 215, 670, 679
dot (.) metacharacter, 497
downcasting, 117–118
E
early loop termination, 348
else if statement, 330–331
else statement, 329–332
enabling assertions
compiling assertion-aware code, 388–389
identifiers versus keywords, 387–388
javac, 388
at runtime, 389
selective, 390–391
encapsulation, 86–89
enclosing class, 682
engines, regex, 488
enhanced for loops, 350–352
entry points, 338
enums
declaring constructors, methods, and variables in, 63-65
equality operators for, 294–295
maps, 584
overview, 60–63
EOFException subclass, 370, 373
equal (=) sign, 191
equal to (= =) operator, 245–246, 292–294, 544
equality operators
for enums, 294–295
overview, 292
for primitives, 292–293
for reference variables, 293–294
equals (= =) operator, 245–246, 292–294, 544
equals( ) method
collections, 562–563
hashCode( ), 548–549
hashcodes, 586
inheritance, 91
maps, 583
overriding, 544–549
wrappers, 245–246
equalsIgnoreCase( ) method, 435–436
equals(java.lang.Object) method, 554
equals(Object) method, 554
error detection and handling. See exceptions
errors, scoping, 201–202
events, 9
ExceptionInInitializerError, 382
exceptions
catch keyword, 357–359
checked, 373–375
declaration and public interface, 371–376
finally block, 359–362
hierarchy of, 366–369
JVM thrown, 379–380
matching, 369–371
programmatic
defined, 379
list of, 382
programmatically thrown, 380–381
propagating uncaught, 362–365
rethrowing same, 376–378
try keyword, 357–359
exclusive-OR (XOR) logical operator, 288, 309–310, 553
execution, threads of, 702, 709, 757
existingDir subdirectory, 454
expressions
assertions, 385–387
for case constant, 335–338
conditional, 346–347
for if statements, 332–334
iteration, 347–348
for statement, 351
for switch statements, 335–338
extends keyword
generic methods, 618
interfaces, 122–124
java.lang.Thread, 705–706
F
fall-through in switch blocks, 338–340
FIFO (first-in, first-out), 564
file navigation
combining I/O classes, 449–452
creating files using class File, 445–447
directories, 452–457
FileWriter and FileReader classes, 447–449
overview, 443–445
FileNotFoundException subclass, 370–371
FileReader class, 443, 447–449
FileWriter class, 444, 447–449
final arguments, 41
final classes, 15–16
final variables, 57–58, 303, 336
final void notify( ) method, 543
final void notifyAll( ) method, 543
final void wait( ) method, 543
finally clause, 359–362
find( ) method, 499
first-in, first-out (FIFO), 564
flags, 507
floating points, 15, 46, 188–189
floor( ) method, 587
floorKey( ) method, 587
flow control
assertions
enabling, 387–391
expression rules, 385–387
overview, 383–385
using appropriately, 392–394
exceptions
catch keyword, 357–359
declaration of, 371–376
defined, 365–366
finally block, 359–362
hierarchy of, 366–369
JVM thrown, 379–380
matching, 369–371
overview, 356–357
programmatically thrown, 380–381
propagating uncaught, 362–365
public interface and, 371–376
rethrowing same, 376–378
try keyword, 357–359
if statements
if-else branching, 329–334
legal expressions for, 332–334
overview, 328
loops
break statement, 352–353
continue statement, 352–353
do, 344–345
for, 345–352
labeled statements, 354–356
unlabeled statements, 353–354
while, 343–344
overview, 327–328
switch statements
break statement in, 338–340
default case, 341–342
fall-through in, 338–340
legal expressions for, 335–338
flush( ) method, 448–449
Foo class
argument-defined anonymous inner classes, 679–680
compiler-generated constructor code, 137
natural order in, 561
overloaded methods, 114
reference variable assignments, 199
shadowing instance variables, 217–218
for loops
conditional expressions, 346–347
declaration, 346
enhanced, 350–352
issues with, 348–350
iteration expressions, 347–348
legacy collections, 598
overview, 345–346
PriorityQueue class, 592
threads, 714
forced exits, 347–348
forcing garbage collection, 260–262
for-each. See for loops
for-in. See for loops
format( ) method, 506–508
formatting
dates and numbers
Calendar class, 477–479
Date class, 476–477
DateFormat class, 480–481
Locale class, 482–485
NumberFormat class, 485–487
orchestrating classes, 474–475
overview, 473
tokenizing
and delimiters, 502
format( ) method, 506–508
overview, 501–502
printf( ) method, 506–508
Scanner class, 504–506
String.split( ) method, 502–504
G
garbage collection
code making objects eligible for
finalize( ) method, 263
forcing, 260–262
isolating references, 259–260
nulling references, 257–258
overview, 257
reassigning reference variables, 258–259
in Java, 255–257
memory management and, 254–255
generics
declaring
classes, 623–627
methods, 627–630
overview, 622–623
legacy code, 597–600
methods, 609–622
mixing with non-generic collections, 601–607
polymorphism and, 607–609
get( ) method, 581, 584, 586, 599, 606
getDateInstance( ) method, 480–481
getInstance( ) method, 477, 480
getName( ) method, 710–711
getProperty( ) method, 795
getState( ) method, 708
greedy quantifiers, 495–497
group( ) method, 499
H
HardToRead class, 543
HAS-A relationships, 96–98
hashCode( ) method
equals( ) method, 548–549
HashSet, 562
Maps, 583
overriding
contract, 554–556
implementing, 552–554
overview, 549–552
real-life hashing, 551
HashMap class
Collection interface, 557, 565
collections, 566
hashCode( ) method, 555–556
LinkedHashMap, 564
Map interface implementation, 563
overriding equals( ), 545
use of, 583
Hashtable class, 557, 560, 564–565
headMap( ) method, 590
headSet( ) method, 590
hexadecimal literals, 187–188
hierarchy of exceptions, 366–369
high cohesion, 152–153
higher( ) method, 587
higherKey( ) method, 587
higher-level classes, 460
highest-priority threads, 724
I
IDE (Integrated Development Environment) tool, 8
identifiers
versus keywords, 387–388
legal, 5–6
Map interface, 563
overview, 2–4
IEEE 754 standard, 15
if statements
if-else branching, 329–332
initialization, 208
legal expressions for, 332–334
overview, 328
IllegalArgumentException, 381–382, 393
IllegalMonitorStateException, 749–750
IllegalStateException, 382
immutability of strings, 426–433
implementation classes, 121–122, 560, 680
implementers, interface, 677–678
implementing
equals( ) method, 546–549
hashCode( ) method, 552–554
interfaces, 120–125
java.lang.Runnable, 706
implicit casts, 193
import statements, 3–4, 11, 799–800, 805–806
imports, static, 806–807
increment (+ +) operator, 302–303
increment expression, 350
indenting, 331–332
IndexOutOfBoundsException, 368
indirect implementations, 296
inheritance
versus dot operator for member access, 27
HAS-A relationship, 96–98
IS-A relationship, 94–95
and serialization, 468–472
and subclasses, 25–26
initialization blocks, 234–237
initializing
arrays
anonymous, 228–230
elements in loop, 225–226
legal element assignments, 230
multidimensional, 233–234
of object references, 231–232
on one line, 226–228
one-dimensional, 232–233
overview, 224–225
primitive, 230–231
reference assignments for one-dimensional, 232–234
local variables, 54
for loops, 346
inner classes
anonymous
argument-defined, 678–680
overview, 673–678
coding regular, 664–668
method-local, 670–672
overview, 661–664
referencing inner or outer instance from within, 668–670
static nested classes, 680–681
insert( ) method, 441, 602–603
insertion points, 576
instance methods, 102
instance variables
array, 206
defined, 51–53
hashCode( ) method, 552–553
object reference, 203–206
primitive, 203–204
protecting, 31
scope of, 201
uninitialized
array, 206
object reference, 203–206
overview, 203
primitive, 203–204
instanceof operator
compiler error, 297–298
equals( ) method, 547
inheritance, 90
IS-A relationship, 233
overview, 295–298
instances
initialization blocks, 234–235, 237
for java.text and java.util classes, 487
static nested classes, 680
instantiating
constructors
chaining, 132–133
default, 135–139
overloaded, 139–145
overview, 130–132
rules for, 133–134
inner classes, 666–668
outer class, 667
static nested classes, 681
threads, 706–708
int hashCode( ) method, 543
int indexOf(object) interface method, 594
int size( ) interface method, 594
int variable, 192
integer literals
decimal, 186
hexadecimal, 187–188
octal, 187
Integrated Development Environment (IDE) tool, 8
interactions, thread
notifyAll( ), 752–757
overview, 746–751
interfaces
as array types, 231
collections
List, 561–562
Map, 563–564
overview, 557–561
Queue, 564–566
Set, 562–563
declaring
constants, 22–23
overview, 19–22
implementers, 677–678
implementing, 120–125
naming standards, 7
overview, 3
relationship with classes, 20
invoking
overloaded methods, 111–113
superclass version of overridden methods, 107–108
I/O
class File, 445–447
combining classes, 449–452
FileReader, 447–449
files and directories, 452–457
FileWriter, 447–449
java.io.Console class, 457–459
overview, 443–459
IOException class, 370–371, 373
IS-A relationship, 94–95, 233, 251, 547
isEmpty( ) method, 755
islands of isolation, 259
isolating references, 259–260
iteration
defined, 560
expressions and for loops, 347–348
J
JAR (Java Archive) files, 802–805, 808
jar command, 803–804
Java 6 compiler. See javac command
Java Archive (JAR) files, 802–805, 808
java command
launching applications with, 793–796
searching for other classes
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
Java Virtual Machine (JVM)
thread scheduler, 716
javac command
assertion-aware code, 388–389
compiling with, 790–793
constructor code generated by, 137
failures, 350
JAR files, 804
searching for other classes
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
warnings, 603
java.io Mini API, 450
java.io.Console class, 457–459
java.lang.Class instances, 737
java.lang.Enum class, 584
java.lang.Object class, 718
java.lang.Runnable interface, 706
java.lang.Thread class, 705–706, 717
java.text class, 487
java.text.DateFormat, 474
java.text.NumberFormat, 474
java.util.ArrayList class, 567
java.util.Calendar, 474
java.util.Collections class, 558, 569
java.util.Date class, 474
java.util.HashMap class, 796
java.util.jar package, 805
java.util.Locale, 474
java.util.NavigableMap interface, 586
java.util.NavigableSet interface, 586
java.util.Properties class, 794
java.util.regex package, 805
java.utils.Arrays.sort( ) method, 571
JButton class, 608
jobs list, 755–756
join( ) method, 716–717, 726–728
jre/lib/ext subdirectory tree, 805
just-in-time array arguments, 229–230
JVM (Java Virtual Machine)
thread scheduler, 716
K
keys, 795
keywords
abstract, 15
catch, 357–359
chart, 6
default, 341–343
extends
generic methods, 618
interfaces, 122–124
java.lang.Thread, 705–706
versus identifiers, 387–388
new, 222
overview, 3
super, 619
throw, 367
try
exceptions, 357–359
with finally block, 359–361
wait( ) method, 750
without catch block, 361
without finally block, 361
L
labeled statements, 354–356
launching applications with java command, 793–796
legacy code, 597–602
legal array element assignments, 230
legal expressions
for case constant, 335–338
for if statements, 332–334
for switch statements, 335–338
legal identifiers, 4
legal overloaded methods, 110
legal overridden methods, 109
legal return types
covariant, 127–128
on overloaded methods, 126–127
on overridden methods, 127–128
returning values, 128–130
length attributes, array, 437
length( ) method, 435–436
length variable, 225–226
LinkedHashMap class, 557, 564–566
LinkedHashSet class, 560, 563, 565
LinkedList class, 562, 564–565, 580
List class, 608
List interface
collections, 561–562
in Collections Framework, 557
converting to arrays, 579
generic declarations, 622
key methods, 594–595
use of, 580–581
List<?> syntax, 620
List<Integer> syntax, 621
List<Object> syntax, 620–621
list.add( ) method, 620
listeners, 9
lists, enumerated. See enums
literals
boolean, 189
character, 189–190
floating-point, 188–189
integer
decimal, 186
hexadecimal, 187–188
octal, 187
live objects, 257
local arrays, 210
local object references, 209–210
local primitives, 207–209
local variables
access member modifiers and, 38–39
array references, 210
assigning one reference variable to another, 210–213
defined, 53–55
inner classes, 671
object references, 209–210
overview, 207
primitives, 207–209
scope of, 201
uninitialized, 203
Locale class, 482–485
logical operators
bitwise, 305
boolean invert, 309–310
non-short-circuit, 308–309
short-circuit, 306–308
XOR, 309–310
loops
break statement, 352–353
continue statement, 352–353
do, 344–345
for
conditional expression, 346–347
declaration, 346
enhanced, 350–352
initialization, 346
issues with, 348–350
iteration expression, 347–348
legacy collections, 598
overview, 345–346
PriorityQueue class, 592
threads, 714
initializing elements in, 225–226
labeled statements, 354–356
unlabeled statements, 353–354
wait( ) in, 753–757
while, 343–344
loose coupling, 152
lower( ) method, 587
lowerKey( ) method, 587
lower-level classes, 460
lower-priority threads, 724
M
Machine class, 754
main( ) method, 546, 665, 702, 710, 713
makeArrayList( ) method, 627
makeInner( ) method, 666
makeWithdrawal( ) method, 734
MANIFEST.MF file, 804
Map interface
collections, 563–564
key methods, 594–595
use of, 583–586
MapTest.main( ) method, 585
Matcher class, 498–501
matching, exception, 369–371
MAX_VALUE constant, 807
meaningfully equivalent instances, 245–246
Meeks, Jonathan, 97
member classes, 662
member declarations
access modifiers
local variables and, 38–39
overview, 24–26
private members, 29–32
protected members, 32–36
public members, 26–29
constructor, 47–48
enum
constructors, methods, and variables in, 63-65
overview, 60–63
nonaccess modifiers
abstract methods, 41–45
final arguments, 41
final methods, 40
methods with var-args, 46–47
native methods, 46
overview, 39
strictfp methods, 46
synchronized methods, 45
variable
array, 55–57
final, 57–58
instance, 51–53
local, 53–55
overview, 49
primitive, 49–51
reference, 51
static, 59–60
transient, 59
volatile, 59
visibility and access, 39
member methods, 662
member modifiers applied to inner classes, 670
member variables, 662. See also instance variables
memory
garbage collection, 257
management and garbage collection, 254–255
and String class, 433–434
metacharacters
and searches, 490–492
and strings, 497–498
META-INF directory, 804
method-local inner classes, 670–672
methods. See also hashCode( ) method; individual methods by name
backed collections, 593–595
chained, 442
comparison of modifiers on, 53
declarations, 41
declaring in enums, 63–65
defined, 2
effects of static on, 150
in interfaces, 20–21
JavaBean signatures for, 10
naming standards, 7
overriding Object
equals( ), 544–549
toString( ), 542–544
overriding rules, 106–107
passing variables into
object reference, 213–214
overview, 213
pass-by-value semantics, 214–215
primitive, 215–218
String class, 434–438
StringBuffer, 440–442
StringBuilder, 440–442
synchronizing static, 737–739
thread scheduler, 717–718
with var-args, 46–47
mkdir( ) method, 453
modifiers. See also individual modifiers by name
applied to inner classes, 670
class access
default, 13–14
public, 14–15
class nonaccess
abstract, 16–19
final, 15–16
member access
local variables and, 38–39
overview, 24–26
private members, 29–32
protected members, 32–36
public members, 26–29
member nonaccess
abstract methods, 41–45
final arguments, 41
final methods, 40
methods with var-args, 46–47
native methods, 46
overview, 39
strictfp methods, 46
synchronized methods, 45
overview, 12–13
variables and methods, 53
Moof class, 546
moofValue instance variable, 546–547
multidimensional arrays, 57, 223, 233–234
multiple inheritance, 100
multiplication (*) operator, 308
myApp directory, 803
myApp.engine package, 804
myApp.utils package, 804
MyInner class, 666
MyOuter class, 666
MyOuter2 class, 670
N
name variable, 586
names.get(0) method, 743
names.remove(0) method, 744
names.size( ) method, 743–744
naming standards
classes, 7
interfaces, 7
JavaBean listeners, 9
JavaBean properties, 8–9
methods, 7
variables, 7
narrowing, 193
native methods, 46
natural order, 561
NavigableMap interface, 566
NavigableSet interface, 566
navigating
files
combining I/O classes, 449–452
creating files using class File, 445–447
directories, 452–457
FileWriter and FileReader classes, 447–449
overview, 443–445
methods relating to, 588
TreeSets and TreeMaps, 586–588
nested classes, static, 680-681. See also inner classes
new keyword, 222
next( ) method, 581
nextXxx( ) methods, 505–506
no-arg constructors, 133–134
NoClassDefFoundError exception, 382
nonabstract methods, 17–18
nonaccess class modifiers
abstract classes, 16–19
defined, 12
final classes, 15–16
nonaccess member modifiers
abstract methods, 41–45
final arguments, 41
final methods, 40
methods with variable argument lists (var-args), 46–47
native methods, 46
overview, 39
strictfp methods, 46
synchronized methods, 45
non-final local variables, 682
non-generic collections, 597, 601–607
non-serializable elements, 472
non-short-circuit AND (&) operator, 288, 308
non-short-circuit logical operators, 308–309
non-short-circuit OR ( | ) operator, 288, 308
non-static inner class instantiation code, 667
non-static methods, 735, 740–741
non-static synchronized methods, 739, 741
nonstatic variables, 147–148
non-synchronized methods, 736–737
non-transient variables, 556
non-type safe code, 602–607
NoSuchElementException class, 743
not equal to (!=) operator, 292
notify( ) method, 542, 746, 748, 752–756
notifyAll( ) method, 542, 746, 752–757
null references, 205, 209, 224, 257–258, 563–564
NullPointerException class, 224, 247, 373, 380, 382
NumberFormat class, 484–487
NumberFormatException class, 381–382
numbers, formatting, 473–487
numeric primitives, 50
O
Object class. See also hashCode( ) method
arrays, 579
influencing thread scheduler, 718
overriding methods
equals( ), 544–549
toString( ), 542–544
overview, 542
object get( ) interface methods, 594
object graphs, 461–465
object next( ) method, 580
object orientation
cohesion, 151–154
constructors
chaining, 132–133
default, 135–139
overloaded, 139–145
overview, 130–132
rules for, 133–134
coupling, 151–153
encapsulation, 86–89
implementing interfaces, 120–125
inheritance
HAS-A relationship, 96–98
IS-A relationship, 94–95
overview, 90–94
legal return types
covariant returns, 127–128
on overloaded methods, 126–127
on overridden methods, 127–128
returning values, 128–130
overloaded methods
invoking, 111–113
legal, 110
overview, 109–110
polymorphism in, 113–115
overridden methods
examples of legal and illegal, 109
invoking superclass version of, 107–108
overview, 103–107
polymorphism, 98–102
reference variable casting, 116–119
statics
accessing, 148–151
overview, 145–148
object reference instance variables, 203–206
object reference variables
arrays of, 231–232
assigning null to, 199
passing into methods, 213–214
Object type, 572
Object[] toArray( ) interface method, 594
ObjectInputStream method, 460–461
object-oriented design, 97
ObjectOutputStream method, 460–461
objects
arrays as, 297
defined, 2
uneligiblizing for garbage collection, 263
wrapper, 239–240
octal literals, 187
one-dimensional arrays, 221–222, 232–233
operands, 298
operators. See also individual operators by name
arithmetic
decrement, 302–303
increment, 302–303
overview, 298
remainder, 299
string concatenation, 299–301
assignment
overview, 288–290
conditional, 304–305
instanceof
compiler error, 297–298
overview, 295–297
logical
bitwise, 305
boolean invert, 309–310
non-short-circuit, 308–309
short-circuit, 306–308
XOR, 309–310
precedence, 290
relational
equality operators, 292–295
overview, 290–291
OR operator
ordered collections, 560
outer classes
instantiating inner class from within, 666–668
overview, 664
referencing from within inner classes, 668–670
static members of, 681
OutOfMemoryError subtype, 375
outside outer class instance code, 666–668
overloaded constructors, 139–145
overloading methods
with boxing and var-args, 249–250
in combination with var-args, 253–254
invoking, 111–113
legal, 110
legal return types on, 126–127
versus overridden methods, 115
polymorphism in, 113–115
when combining widening and boxing, 251–253
widening reference variables, 250–251
overridden methods. See also hashCode( ) method
invoking superclass version of, 107–108
legal and illegal, 109
legal return types on, 127–128
Object
equals( ), 544–549
toString( ), 542–544
versus overloaded methods, 115
overview, 103–107
polymorphism in, 113–115
versus static methods, 151
P
parameterized type, 598, 626–628
parameters, 46
parentheses, 300
parse( ) method, 481
parseXxx( ) methods, 241
parsing
locating data via pattern matching, 498-501
overview, 487–488
searches
greedy quantifiers, 495–497
overview, 488–489
predefined dot, 495
simple, 489–490
strings and metacharacters, 497–498
using metacharacters, 490–492
using quantifiers, 492–495
Part class, 566
pass-by-value semantics, 214–215
passing variables into methods
object reference variables, 213–214
overview, 213
pass-by-value semantics, 214–215
primitive variables, 215–218
Pattern class, 498–501
pattern matching, 498–501
poll( ) method, 562, 588, 591–592
pollFirst( ) method, 588
pollFirstEntry( ) method, 588
pollFirstXxx( ) method, 591
polling, 588
pollLast( ) method, 588
pollLastEntry( ) method, 588
polymorphism
anonymous inner classes, 675
defined, 92
generics and, 607–610
in overloaded methods, 113–115
in overridden methods, 113–115
overriden methods, 108
overview, 98–102
pool, String constant, 434
populateList( ) method, 570
precedence, 299
precision format string element, 507
predefined dot, 495
preventing thread execution, 720–721
primitive arrays, 230–231
primitive instance variables, 203–204
primitive literals
boolean, 189
character, 189–190
defined, 186
floating-point, 188–189
integer, 186–188
string, 190
primitive return types, 128–129
primitive variables
assignments, 191–193
casting
assigning floating-point numbers, 196
assigning literals too large for, 196–197
assigning one primitive to another, 198
overview, 193–195
declaration, 49–51
defined, 49
equality operators for, 292–293
passing into methods, 215–218
ranges, 49–51
printf( ) method, 506–508
PrintWriter class, 444
priorities, thread, 724–728
PriorityQueue class
backed collections, 591–592
Collection interface, 565
methods, 594
overview, 564–566
private access, 32
private constructors, 133
private members, 29–32
private method-local inner class, 672
private variables, 733
programmatic exceptions
defined, 379
list of, 382
programmatically thrown exceptions, 380–381
propagating uncaught exceptions, 362–365
properties, system, 794–795
protected access, 37
protected members, 32–36
protected method-local inner class, 672
public access
classes, 14–15
effects of, 32
public boolean
equalsIgnoreCase(String s)
method, 436
public char charAt(int index) method, 435
public int length( ) method, 436
public interface, 371–376
public members, 26–29
public methods, 11, 392–393, 672
public modifier, 21
public static String toString( ) methods, 593
public static void sort( ) method, 593
public String concat(String s) method, 435–436
public String replace(char old, char new) method, 436
public String substring( ) methods, 436–437
public String toLowerCase( ) method, 437
public String toString( ) method, 438, 441–442
public String toUpperCase( ) method, 438
public String trim( ) method, 438
public StringBuilder delete(int start, int end) method, 440–441
public StringBuilder insert(int offset, String s) method, 441
public synchronized StringBuffer append(String s) method, 440
public synchronized StringBuffer reverse( ) method, 441
put(key, value) interface method, 594
Q
quantifiers
greedy, 495–497
and searches, 492–495
Queue interface, 557, 564–566, 594–595
R
race conditions, 733
RandomAccess interface, 562
ranges, primitive variable, 49–51
reachable references, 257
read( ) method, 746
readObject( ) method, 465–468
readPassword method, 457
reassigning reference variables, 258–259
Red-Black tree structure, 563
reference type, 113
reference variables
anonymous inner classes, 674, 676
assignments, 198–200
casting, 116–119
declaring, 51
equality operators for, 293–294
isolating, 259–260
nulling, 257–258
polymorphism, 99
reassigning, 258–259
and string objects, 429
widening, 250–251
references, reachable, 257
referencing instances from within inner classes, 668–670
reflexiveness of equals( ) method, 549
regex (regular expressions)
engines, 488
Matcher class, 498–501
Pattern class, 498–501
searches
dot metacharacter, 495
greedy quantifiers, 495–497
overview, 488–489
simple, 489–490
string and metacharacters, 497–498
using metacharacters, 490–492
using quantifiers, 492–495
tokenizing, 501–506
regions, 500
regular expressions (regex)
engines, 488
Matcher class, 498–501
Pattern class, 498–501
searches
dot metacharacter, 495
greedy quantifiers, 495–497
overview, 488–489
simple, 489–490
string and metacharacters, 497–498
using metacharacters, 490–492
using quantifiers, 492–495
tokenizing, 501–506
regular inner classes, 664–668
relational operators
equality
for enums, 294–295
overview, 292
for primitives, 292–293
for reference variables, 293–294
overview, 290–291
relative paths, 801–802
remainder (%) operator, 299
removeFirst( ) method, 743–744
remove(index) interface method, 594
remove(key) interface method, 594
remove(object) interface method, 594
replace( ) method, 435–436
rethrowing exceptions, 376–378
return types, legal
covariant returns, 127–128
on overloaded methods, 126–127
on overridden methods, 127–128
returning values, 128–130
roll( ) method, 479
root directory, 804
rules for constructors, 133–134
run( ) method
Thread class
completion, 716
instantiating, 708
leaving running state, 728
making thread, 704–705
order of actions, 714
overview, 710
using wait( ) in loop, 755–757
Runnable interface, 678, 705–709
runnable threads, 716–719, 726
running multiple threads, 713–716
runtime
disabling assertions at, 390
enabling assertions at, 389
Runtime class, 261
RuntimeException class, 366–368, 373–374
S
s variable, 200
scheduler, thread, 716–718, 728
searching
arrays, 576–578
Java Archive files and, 803–805
for other classes, 796–802
classpaths, 797–798
overview, 796–797
packages, 799–801
relative and absolute paths, 801–802
simple searches, 489–490
TreeSets and TreeMaps, 586–588
using metacharacters, 490–492
using quantifiers, 492–495
seeOuter( ) method, 670
selective enabling and disabling of assertions, 390–391
semantics, pass-by-value, 214–215
semicolons (;), 17, 41, 344–345, 675
serial numbers, 566
serialization
and inheritance, 468–472
object graphs, 461–465
ObjectInputStream methods, 460–461
ObjectOutputStream method, 460–461
overview, 459–460
readObject method, 465–468
and statics, 472–473
transient variables, 59
writeObject method, 465–468
Set interface
implementations for collections, 562–563
key methods, 594–595
use of, 581–583
Set keySet( ) interface method, 594
setParseIntegerOnly( ) method, 486
setPriority( ) method, 725
setProperty method, 795
shadowing variables, 54–55, 201, 216–218
short-circuit AND (&&) operator, 306, 308, 548
short-circuit logical operators, 306–308
short-circuit OR ( | | ) operator, 306, 308
shortcut syntax, array, 226–228
side effects, assertion, 394
signed number types, 49
simple searches, 489–490
sleep( ) method, 717, 721, 723, 727, 757
sleeping threads, 719–724
sort( ) method
ArrayList class, 569
Collections class, 571–572, 574
SortedMap class, 591
SortedSet class, 591
sorting collections
Arrays class, 576
Comparable interface, 571–573
Comparator interface, 574–575
defined, 561
overview, 569–571
source directories, 792
source file declaration rules, 11–12
-source option, javac command, 790
split( ) method, 502–504
spontaneous wakeup, 755
square brackets, 219–220
StackOverflowError subtype, 380, 382
start( ) method
Matcher class, 499
threads, 708–709, 716, 718, 757
starting threads
overview, 709–712
and running multiple, 713–716
thread scheduler, 716–718
statements. See also decision statements assert, 386–389, 394
break
labeled, 354–356
in switch blocks, 338–340
switch statements, 335
unlabeled, 353–354
use of, 352–353
continue
labeled, 354–356
overview, 352–353
unlabeled, 353–354
else, 329–332
else if, 330–331
import, 3–4, 11, 799–800, 805–806
labeled, 354–356
unlabeled, 353–354
states
defined, 2
thread
overview, 718–720
preventing execution, 720–721
priorities and yield( ), 724–728
sleeping, 721–724
static boolean equals( ) method, 593
static Comparator reverseOrder( ) method, 593
static compile( ) method, 499
static imports, 806–807
static initialization blocks, 234–235
static inner classes, 680
static int binarySearch( ) method, 593
static List asList( ) method, 593
static methods
accessing, 148–151
blocked threads, 720
defined, 59–60
inner classes, 667–668
local classes declared in, 672
overview, 145–151
sort( ), 576
synchronizing, 737–741
in Thread class, 756
Thread.sleep( ), 721
static modifier, 45, 59–60, 145, 682
static nested classes, 680–682
static synchronized methods, 739, 741
static Thread.currentThread( ) method, 711
static Thread.yield( ) method, 726
static variables
accessing, 148–151
defined, 59–60
overview, 145–151
scope of, 201
and serialization, 472–473
static void reverse( ) method, 593
static void sort( ) method, 593
stop( ) method, 720
Stream classes, 444
String class
creating new strings, 434
immutability, 426–433
important methods, 434–438
and memory, 433–434
overriding equals( ), 546
overview, 426
reference variables, 211–213
split( ) method, 502–504
toString( ) method, 543
string concatenation operator, 299–301
String constant pool, 434
StringBuffer class
important methods, 440–442
overview, 438–440
synchronizing code, 738–739
thread-safe, 742
StringBuilder class
important methods, 440–442
overview, 438–440
thread-safe, 742
StringIndexOutOfBoundsException subclass, 368
strings
collections, 566
generics, 596
Maps, 584
and metacharacters, 497–498
overview, 426
reference variables, 211–213
String class
creating new, 434
immutability, 426–433
important methods, 434–438
and memory, 433–434
overview, 426
StringBuffer class
important methods, 440–442
overview, 438–440
StringBuilder class
important methods, 440–442
overview, 438–440
synchronizing code, 738
subclasses
inner classes, 677
versus interfaces, 122
protected and default members, 32–34
Thread class, 705
subMap( ) method, 589–590
subSet( ) method, 590
substring( ) method, 435–437
subtraction (−) operator, 306
subXxx( ) method, 591
Sun's Java Code Conventions, 4
super constructors, 136–139
super keyword, 619
superclasses, 3
suspend( ) method, 720
switch statements
break statement in, 335, 338–340
default case, 341–342
fall-through in, 338–340
legal expressions for, 335–338
symmetry of equals( ) method, 549
synchronized methods
in code synchronization, 734–740
defined, 45
thread interaction, 751
Vector, 562
wait( ) in loops, 756
synchronizedList( ) method, 744
synchronizing code
atomic operations, 733–735
deadlock, 745–746
if thread can't get lock
locks, 735–737
overview, 728–733
static methods, 737–739
thread-safe classes, 742–744
when synchronization is needed, 740–742
syntax
array shortcut, 226–228
generics, 598
system properties, 794–795
System.gc( ) method, 261
System.out.println( ) method, 504, 542, 630
T
T[ ] toArray(T[ ]) interface method, 594
tailMap( ) method, 590
tailSet( ) method, 590
tailXxx( ) method, 591
target Runnables, 707
ternary operators, 304
test expressions, 347
TestClass class, 800
testIt( ) method, 33
Thread class
extending, 705–706
final methods, 40
influencing thread scheduler, 717
instantiating thread, 706–708
one-dimensional arrays, 222
run( ) method completion, 716
starting thread, 709–712
thread scheduler, 716–718, 728
threads
blocked, 719–720
defining, 705–706
instantiating, 706–708
interaction
notifyAll( ), 752–757
overview, 746–751
making, 704–705
overview, 701–704
sleeping, 719–724
starting
overview, 709–712
and running multiple, 713–716
thread scheduler, 716–718
states and transitions
overview, 718–720
preventing execution, 720–721
priorities, 724–728
sleeping, 721–724
yield( ) method, 726
synchronizing code
atomic operations, 733–735
deadlock, 745–746
if thread can't get lock, 739-740
locks, 735–737
overview, 728–733
static methods, 737–739
thread-safe classes, 742–744
when needed, 740–742
waiting, 719–720
thread-safe classes, 742–744
Thread.sleep( ) method, 721
throw keyword, 367
Throwable class, 366–368
thrown exceptions, 357
tight coupling, 152
tokenizing
and delimiters, 502
format( ) method, 506–508
overview, 501–502
printf( ) method, 506–508
Scanner class, 504–506
String.split( ) method, 502–504
toLowerCase( ) method, 437
toString( ) method
overriding equals( ), 548
public string, 438
in String class, 435
StringBuffer class, 441–442
wrapper conversion, 242
toUpperCase( ) method, 438
toXxxString( ) method, 242–243
transient method-local inner class, 672
transient modifier, 465
transient variables, 59, 460, 470, 555–556
transitions, thread
overview, 718–720
preventing execution, 720–721
priorities and yield( ), 724–728
sleeping, 721–724
yield( ), 724–728
transitivity of equals( ) method, 549
TreeMap class
backed collections, 589–590
overview, 564
searching, 586–588
subMap( ), 589
TreeSet class
backed collections, 590
Collection interface, 565
searching, 586–588
trim( ) method, 438
try keyword
exceptions, 357–359
with finally block, 359–361
wait( ) method, 750
without catch block, 361
without finally block, 361
t.start( ) method, 713
two-dimensional arrays, 223
type erasure, 604–605
type safe code, 602–606
U
UML (Unified Modeling Language), 97
unboxing
equals( ) method, 245–246
equals operator, 245–246
overloading
with var-args and, 249–250
when combining widening and, 252–253
overview, 244–245
in switch statements, 337
use of, 246–247
uncaught exceptions, propagating, 362–365
unchecked exceptions, 373, 375
Unicode characters, 51, 189, 426–427
Unified Modeling Language (UML), 97
uninitialized variables
array instance, 206
object reference instance, 203–206
overview, 203
primitive instance, 203–204
unique hashcodes, 585
unique identifiers, 563
unlabeled statements, 353–354
unwinding stack, 367
upcasting, 118
use cases, date and number, 475
V
valueOf( ) methods, 240–241
values, constant, 23
var-args (variable argument lists)
declaration rules for, 47
methods with, 46–47
syntax, 796
variables. See also individual variables by name
assignment operators
assigning one primitive to another, 198
floating-point numbers, 196
literals too large for, 196–197
overview, 190–191
primitive, 191–193
primitive casting, 193–195
reference, 198–200
scope, 200–202
comparison of modifiers on, 53
declarations
arrays, 55–57
in enums, 63–65
final, 57–58
generics and polymorphism, 608
instance, 51–53
local, 53–55
overview, 49
primitive, 49–51
reference, 51
static, 59–60
transient, 59
volatile, 59
effects of static on, 150
in interfaces, 20–21
local
access member modifiers and, 38–39
array references, 210
assigning one reference to another, 210–213
defined, 53–55
inner classes, 671
object references, 209–210
overview, 207
primitives, 207–209
scope of, 201
uninitialized, 203
naming standards, 7
passing into methods
object reference variables, 213–214
overview, 213
pass-by-value semantics, 214–215
primitive variables, 215–218
uninitialized
array instance, 206
object reference instance, 203–206
overview, 203
primitive instance, 203–204
VirtualMachineError subtype, 375
void finalize( ) method, 543
void return types, 129
volatile variables, 59
W
wait( ) method
lock status, 740
in loops, 753–757
overview, 718
thread interaction, 746–752
threads leaving running state, 728
waiting threads, 719–720
wakeup, spontaneous, 755
warnings, compiler, 603
widening
overloading when combining boxing and, 251–253
reference variables, 250–251
wrapper classes, 251
width format string element, 507
wrappers
autoboxing
equals( ) method, 245–246
equals operator, 245–246
overview, 244–245
use of, 246–247
classes
overriding equals( ), 546
overview, 237–238
and widening, 251
constructors, 239
conversion methods, 243
conversion utilities
parseXxx( ) methods, 241
toString( ) method, 242
toXxxString( ) method, 242–243
valueOf( ) method, 241
xxxValue( ) methods, 240–241
NullPointerException, 247
valueOf( ) methods, 240
wrapping I/O classes, 449–452
writeObject( ) method, 465–468
X
x variable, 200
x2 variable, 200
x3 variable, 200
−Xlint:unchecked flag, 605
XOR (exclusive-OR) logical operator, 288, 309–310, 553
xxxValue( ) methods, 240–241
Y
y variable, 200
yield( ) method, 724–728
Z
z variable, 200