Java Rules

Table of Contents......Page 7
Preface for Volume 2......Page 13
About This Book......Page 19
A Java Tradition......Page 29
A Pet Peeve......Page 31
Fields and Methods......Page 33
1.1 Introduction......Page 34
1.2 Fields......Page 35
1.3.1 Automatic Initialization Using Standard Default Values......Page 38
1.3.2 Initialization Blocks......Page 39
1.3.3 Constructors......Page 42
1.3.3.1 Reference Constructors......Page 48
1.3.3.2 Alternative Constructor Designs......Page 50
1.4 Field Initialization Anomalies......Page 55
1.4.1 The Problem of Forward Referencing......Page 56
1.4.2 Invoking Overridden Methods During Object Initialization......Page 61
1.4.3 Inlined Constants Always Appear to Have Been Initialized......Page 65
1.4.4 The Variable Initializer for a Field is Always Executed......Page 68
1.4.5 StackOverflowError During Object Initialization......Page 70
1.4.6 Throwing Checked Exceptions During Initialization......Page 73
1.5 Constants......Page 81
1.5.1 Compile-Time Constant Expressions......Page 82
1.5.2 Inlined Constants......Page 89
1.5.2.1 The Problem of Changeable Inlined Constants......Page 95
1.5.3 Declaring Mutable Objects final......Page 101
1.5.4 Blank Finals......Page 102
1.5.5 Enumerated Types......Page 106
1.5.6 Declaring Local Variables and Parameters final......Page 126
1.5.7 The Constant Interface Antipattern......Page 130
1.6 Methods......Page 131
1.6.1 abstract Methods......Page 134
1.6.2 Result Types and the return Statement......Page 139
1.6.2.1 Using Return Values to Indicate Failure......Page 142
1.6.3 Formal Parameter Lists......Page 144
1.6.3.1 Argument Checks......Page 147
1.6.3.2 On const References......Page 155
1.6.3.3 Making Defensive Copies......Page 160
1.6.4 The throws Clause......Page 165
1.7 Local Variables......Page 174
1.8 “Write Once, Compile Anywhere”......Page 179
1.8.1 Definite Assignment......Page 181
1.8.2 Unreachable Statements......Page 184
1.9 Qualifying Type versus Compile-Time Declaration......Page 188
1.10 The Five General Forms......Page 193
1.10.1 The Meaning of a Simple Field or Method Name......Page 198
1.10.2 Method Invocation Chaining......Page 204
1.10.3 Casting a Target Reference......Page 206
1.10.4 Accessing static Members using a Primary Expression......Page 208
1.11 Method Signatures......Page 209
1.11.1 The Compiler-Enforced Method Contract......Page 215
1.11.1.1 throws Clause Conflicts in abstract Methods......Page 221
1.11.1.2 Covariant Result Types......Page 224
1.11.2 Overloaded Methods......Page 225
1.11.3 Overriding and Dynamic Method Lookup......Page 233
1.11.3.1 The invokeinterface machine instruction......Page 241
1.12 Method Forwarding......Page 246
Scope, Shadowing, and Qualified Access......Page 247
2.1 Introduction......Page 248
2.2 Namespaces......Page 249
2.2.1 The Meaning of a Simple or Partially Qualified Name......Page 252
2.2.2 Disambiguating Type Names......Page 254
2.3 The Fundamentals of Lexical Scoping......Page 258
2.3.1 The Mysterious Scope Hole......Page 266
2.3.3 Members Shadow Declarations in Enclosing Scopes......Page 268
2.3.4 The Scope of Types in the Unnamed Package......Page 271
2.3.5 Circular Dependencies in Type Declarations......Page 276
2.4 Shadowing......Page 278
2.5 Obscuring......Page 281
2.6 Observable Compilation Units and Packages......Page 284
2.7 Qualified Access......Page 286
2.8 Access Control......Page 290
2.8.1 The protected Access Modifier......Page 301
2.8.2 Full Access to the Members of an Enclosing Class......Page 312
2.8.3 Members More Accessible Than Their Class Type......Page 315
2.8.4 Accessing the Implementation of Same Class Objects......Page 323
2.9 Encapsulation......Page 324
3.1 Introduction......Page 329
3.2 Hiding......Page 332
3.3 The Definition of Baseclass......Page 340
3.4 The Definition of Related Classes......Page 341
3.5 Generalization in Inheritance Hierarchies......Page 342
3.6 Inheritance......Page 344
3.6.1 Interface Inheritance......Page 345
3.6.2 Implementation Inheritance......Page 347
3.7 Do Interfaces Extend the Object Class?......Page 362
3.8.1 Re-Inheritance......Page 367
3.8.2 Ambiguous Names Related to Inheritance......Page 368
3.8.3 Inheriting Methods With the Same Signature......Page 370
3.9 Designing Extensible Classes......Page 374
3.10 Capping a Class Hierarchy......Page 387
Expressions, Statements, and Blocks......Page 391
4.1 Introduction......Page 392
4.2 Expressions......Page 393
4.2.1 Primary Expressions......Page 397
4.2.2 Expression Statements and Other Top-Level Expressions......Page 402
4.3 Operator Expressions......Page 405
4.3.1 Numeric Promotion......Page 407
4.3.2 Operator Order of Precedence and Parenthesized Expressions......Page 415
4.3.3 The Associative Property of Operators......Page 428
4.3.4 Nondestructive Operators......Page 430
4.4 Exceptions are Precise......Page 431
4.5 The 38 Unary, Binary, and Ternary Operators......Page 435
4.5.1 Increment and Decrement Operators -- and ++......Page 436
4.5.2 Negation Operators -, ~, and !......Page 438
4.5.3 The Elementary School Operators......Page 444
4.5.4 Remainder Operator %......Page 446
4.5.5 Boolean Logical Operators &&, ||, &, |, and ^......Page 450
4.5.6 Bitwise Operators &, |, ^, >>, >>>, and <<......Page 454
4.5.7 Ternary Conditional Operator ?:......Page 465
4.5.8 The Simple and Compound Assignment Operators......Page 470
4.6 The instanceof Type Comparison Operator......Page 473
4.7 A Bitwise Primer......Page 475
4.7.1 Bits......Page 477
4.7.2 Converting Nybbles to Hexadecimal Digits......Page 492
4.7.3 General-Purpose Integer to String Conversion Methods......Page 498
4.7.4 Unsigned Bytes......Page 501
4.7.5 Some Miscellaneous Uses of the Bitwise Operators......Page 523
4.8 Statements......Page 526
4.8.1 Control-flow Statements......Page 529
4.8.1.1 The switch Statement......Page 538
4.8.1.2 The for Statement......Page 546
4.8.2 Labeled Statements......Page 554
4.8.3 Control-transfer Statements (a.k.a. Abrupt Completion)......Page 560
4.8.3.1 The continue Statement......Page 561
4.8.3.2 The break Statement......Page 562
4.9 Blocks......Page 566
Type Conversions and the Cast Operator......Page 571
5.1 Introduction......Page 572
5.2 The Type of a Variable or Expression versus the Class of an Object......Page 573
5.2.1 The Phrase “type of an object” is in Prevalent Use......Page 576
5.2.2 The Term class type is Where Everything Goes Afoul......Page 577
5.3 Java is a Strongly Typed Language......Page 583
5.4 Substitution is a Higher Concept than Polymorphism......Page 587
5.5 Forbidden Conversions......Page 595
5.6 Permitted Conversions......Page 597
5.6.1 Identity Conversions......Page 600
5.6.2 Primitive Type Conversions......Page 601
5.6.2.1 Widening Primitive Conversions......Page 604
5.6.2.2 Narrowing Primitive Conversions......Page 605
5.6.3 Reference Type Conversions......Page 612
5.6.3.1 Widening Reference Conversions......Page 614
5.6.3.2 Narrowing Reference Conversions......Page 619
5.7 Conversion Contexts......Page 623
5.7.1 Simple Assignment Conversion Context......Page 627
5.7.1.1 The ArrayStoreException......Page 631
5.7.2 Method Invocation Conversion Context......Page 632
5.7.3 Method Return Conversion Context......Page 636
5.7.4 The Cast Operator......Page 638
5.7.5 The Implicit Cast in a Compound Assignment Operation......Page 643
5.8 Overloaded Method Matching......Page 644
5.8.1 Choosing The Most Specific Applicable Method......Page 645
5.8.2 The Declaring Class of Applicable Methods......Page 650
5.9 Value Set Conversions......Page 656
Assertions, Exceptions, and Logging......Page 659
6.1 Introduction......Page 660
6.2 Assertions......Page 661
6.2.1 Preconditions, Postconditions, and Invariants......Page 671
6.2.2 assert false and Logic Traps (or Control-flow Invariants)......Page 679
6.2.3 Catching CloneNotSupportedException......Page 682
6.3 An Execution Stack Primer......Page 685
6.4 The Exception Mechanism......Page 690
6.5 The Throwable Class Hierarchy......Page 698
6.5.1 General Exception Classes......Page 723
6.5.1.1 Umbrella Exceptions......Page 729
6.5.2 Unspecified Runtime Exceptions and Errors......Page 736
6.5.2.1 The Chicken Little “The Sky is Falling” Problem......Page 754
6.5.3 Asynchronous Exceptions......Page 759
6.6 Throwable Objects......Page 762
6.6.1 The Loggable Interface......Page 767
6.7 The throw Statement......Page 768
6.8 The try Statement......Page 785
6.8.1 The catch Clause......Page 791
6.8.1.1 Catchall Exception Handlers......Page 799
6.8.2 The finally Clause......Page 817
6.8.2.1 try-finally as a Control-flow Statement......Page 818
6.8.2.2 Releasing System Resources......Page 823
6.9 Exception Handling......Page 859
6.9.1 Rethrowing the Same Exception......Page 864
6.9.2 Exception Translation and Chaining......Page 867
6.9.3 Squelching an Exception......Page 874
6.9.4 Setting an Error Flag......Page 878
6.9.5 Retry......Page 879
6.9.6 Try an Alternative......Page 881
6.10 Uncaught Exceptions......Page 883
6.10.1 Top-level Exception Handlers......Page 884
6.10.1.1 The AWTExceptionHandler Class......Page 908
6.10.1.2 The UncaughtException Class......Page 917
6.10.2 A Stack Trace Primer......Page 922
6.11 Logging......Page 936
6.11.1 The Logger Namespace......Page 952
6.11.2 Logging Configuration......Page 957
6.11.3 Logging Methods......Page 975
6.11.4 The Cleaner Thread (A Shutdown Hook in LogManager)......Page 984
Vocabulary List......Page 989
Index......Page 997