Table of Contents

Preface

Preface to the Second Edition

1.1 Example Programs

1.2 Notation

1.3 Relationship to Predefined Classes and Interfaces

1.4 References

2.1 Context-Free Grammars

2.2 The Lexical Grammar

2.3 The Syntactic Grammar

2.4 Grammar Notation

3.1 Unicode

3.2 Lexical Translations

3.3 Unicode Escapes

3.4 Line Terminators

3.5 Input Elements and Tokens

3.6 White Space

3.7 Comments

3.8 Identifiers

3.9 Keywords

3.10 Literals

3.10.1 Integer Literals

3.10.2 Floating-Point Literals

3.10.3 Boolean Literals

3.10.4 Character Literals

3.10.5 String Literals

3.10.6 Escape Sequences for Character and String Literals

3.10.7 The Null Literal

3.11 Separators

3.12 Operators

4.1 The Kinds of Types and Values

4.2 Primitive Types and Values

4.2.1 Integral Types and Values

4.2.2 Integer Operations

4.2.3 Floating-Point Types, Formats, and Values

4.2.4 Floating-Point Operations

4.2.5 The boolean Type and boolean Values

4.3 Reference Types and Values

4.3.1 Objects

4.3.2 The Class Object

4.3.3 The Class String

4.3.4 When Reference Types Are the Same

4.4 Where Types Are Used

4.5 Variables

4.5.1 Variables of Primitive Type

4.5.2 Variables of Reference Type

4.5.3 Kinds of Variables

4.5.4 final Variables

4.5.5 Initial Values of Variables

4.5.6 Types, Classes, and Interfaces

5.1 Kinds of Conversion

5.1.1 Identity Conversions

5.1.2 Widening Primitive Conversion

5.1.3 Narrowing Primitive Conversions

5.1.4 Widening Reference Conversions

5.1.5 Narrowing Reference Conversions

5.1.6 String Conversions

5.1.7 Forbidden Conversions

5.1.8 Value Set Conversion

5.2 Assignment Conversion

5.3 Method Invocation Conversion

5.4 String Conversion

5.5 Casting Conversion

5.6 Numeric Promotions

5.6.1 Unary Numeric Promotion

5.6.2 Binary Numeric Promotion

6.1 Declarations

6.2 Names and Identifiers

6.3 Scope of a Declaration

6.3.1 Shadowing Declarations

6.3.2 Obscured Declarations

6.4 Members and Inheritance

6.4.1 The Members of a Package

6.4.2 The Members of a Class Type

6.4.3 The Members of an Interface Type

6.4.4 The Members of an Array Type

6.5 Determining the Meaning of a Name

6.5.1 Syntactic Classification of a Name According to Context

6.5.2 Reclassification of Contextually Ambiguous Names

6.5.3 Meaning of Package Names

6.5.3.1 Simple Package Names

6.5.3.2 Qualified Package Names

6.5.4 Meaning of PackageOrTypeNames

6.5.4.1 Simple PackageOrTypeNames

6.5.4.2 Qualified PackageOrTypeNames

6.5.5 Meaning of Type Names

6.5.5.1 Simple Type Names

6.5.5.2 Qualified Type Names

6.5.6 Meaning of Expression Names

6.5.6.1 Simple Expression Names

6.5.6.2 Qualified Expression Names

6.5.7 Meaning of Method Names

6.5.7.1 Simple Method Names

6.5.7.2 Qualified Method Names

6.6 Access Control

6.6.1 Determining Accessibility

6.6.2 Details on protected Access

6.6.2.1 Access to a protected Member

6.6.2.2 Qualified Access to a protected Constructor

6.6.3 An Example of Access Control

6.6.4 Example: Access to public and Non-public Classes

6.6.5 Example: Default-Access Fields, Methods, and Constructors

6.6.6 Example: public Fields, Methods, and Constructors

6.6.7 Example: protected Fields, Methods, and Constructors

6.6.8 Example: private Fields, Methods, and Constructors

6.7 Fully Qualified Names and Canonical Names

6.8 Naming Conventions

6.8.1 Package Names

6.8.2 Class and Interface Type Names

6.8.3 Method Names

6.8.4 Field Names

6.8.5 Constant Names

6.8.6 Local Variable and Parameter Names

7.1 Package Members

7.2 Host Support for Packages

7.2.1 Storing Packages in a File System

7.2.2 Storing Packages in a Database

7.3 Compilation Units

7.4 Package Declarations

7.4.1 Named Packages

7.4.2 Unnamed Packages

7.4.3 Observability of a Package

7.4.4 Scope of a Package Declaration

7.5 Import Declarations

7.5.1 Single-Type-Import Declaration

7.5.2 Type-Import-on-Demand Declaration

7.5.3 Automatic Imports

7.5.4 A Strange Example

7.6 Top Level Type Declarations

7.7 Unique Package Names

8.1 Class Declaration

8.1.1 Class Modifiers

8.1.1.1 abstract Classes

8.1.1.2 final Classes

8.1.1.3 strictfp Classes

8.1.2 Inner Classes and Enclosing Instances

8.1.3 Superclasses and Subclasses

8.1.4 Superinterfaces

8.1.5 Class Body and Member Declarations

8.2 Class Members

8.2.1 Examples of Inheritance

8.2.1.1 Example: Inheritance with Default Access

8.2.1.2 Inheritance with public and protected

8.2.1.3 Inheritance with private

8.2.1.4 Accessing Members of Inaccessible Classes

8.3 Field Declarations

8.3.1 Field Modifiers

8.3.1.1 static Fields

8.3.1.2 final Fields

8.3.1.3 transient Fields

8.3.1.4 volatile Fields

8.3.2 Initialization of Fields

8.3.2.1 Initializers for Class Variables

8.3.2.2 Initializers for Instance Variables

8.3.2.3 Restrictions on the use of Fields during Initialization

8.3.3 Examples of Field Declarations

8.3.3.1 Example: Hiding of Class Variables

8.3.3.2 Example: Hiding of Instance Variables

8.3.3.3 Example: Multiply Inherited Fields

8.3.3.4 Example: Re-inheritance of Fields

8.4 Method Declarations

8.4.1 Formal Parameters

8.4.2 Method Signature

8.4.3 Method Modifiers

8.4.3.1 abstract Methods

8.4.3.2 static Methods

8.4.3.3 final Methods

8.4.3.4 native Methods

8.4.3.5 strictfp Methods

8.4.3.6 synchronized Methods

8.4.4 Method Throws

8.4.5 Method Body

8.4.6 Inheritance, Overriding, and Hiding

8.4.6.1 Overriding (by Instance Methods)

8.4.6.2 Hiding (by Class Methods)

8.4.6.3 Requirements in Overriding and Hiding

8.4.6.4 Inheriting Methods with the Same Signature

8.4.7 Overloading

8.4.8 Examples of Method Declarations

8.4.8.1 Example: Overriding

8.4.8.2 Example: Overloading, Overriding, and Hiding

8.4.8.3 Example: Incorrect Overriding

8.4.8.4 Example: Overriding versus Hiding

8.4.8.5 Example: Invocation of Hidden Class Methods

8.4.8.6 Large Example of Overriding

8.4.8.7 Example: Incorrect Overriding because of Throws

8.5 Member Type Declarations

8.5.1 Access Modifiers

8.5.2 Static Member Type Declarations

8.6 Instance Initializers

8.7 Static Initializers

8.8 Constructor Declarations

8.8.1 Formal Parameters

8.8.2 Constructor Signature

8.8.3 Constructor Modifiers

8.8.4 Constructor Throws

8.8.5 Constructor Body

8.8.5.1 Explicit Constructor Invocations

8.8.6 Constructor Overloading

8.8.7 Default Constructor

8.8.8 Preventing Instantiation of a Class

9.1 Interface Declarations

9.1.1 Interface Modifiers

9.1.1.1 abstract Interfaces

9.1.1.2 strictfp Interfaces

9.1.2 Superinterfaces and Subinterfaces

9.1.3 Interface Body and Member Declarations

9.1.4 Access to Interface Member Names

9.2 Interface Members

9.3 Field (Constant) Declarations

9.3.1 Initialization of Fields in Interfaces

9.3.2 Examples of Field Declarations

9.3.2.1 Ambiguous Inherited Fields

9.3.2.2 Multiply Inherited Fields

9.4 Abstract Method Declarations

9.4.1 Inheritance and Overriding

9.4.2 Overloading

9.4.3 Examples of Abstract Method Declarations

9.4.3.1 Example: Overriding

9.4.3.2 Example: Overloading

9.5 Member Type Declarations

10.1 Array Types

10.2 Array Variables

10.3 Array Creation

10.4 Array Access

10.5 Arrays: A Simple Example

10.6 Array Initializers

10.7 Array Members

10.8 Class Objects for Arrays

10.9 An Array of Characters is Not a String

10.10 Array Store Exception

11.1 The Causes of Exceptions

11.2 Compile-Time Checking of Exceptions

11.2.1 Why Errors are Not Checked

11.2.2 Why Runtime Exceptions are Not Checked

11.3 Handling of an Exception

11.3.1 Exceptions are Precise

11.3.2 Handling Asynchronous Exceptions

11.4 An Example of Exceptions

11.5 The Exception Hierarchy

11.5.1 Loading and Linkage Errors

11.5.2 Virtual Machine Errors

12.1 Virtual Machine Start-Up

12.1.1 Load the Class Test

12.1.2 Link Test: Verify, Prepare, (Optionally) Resolve

12.1.3 Initialize Test: Execute Initializers

12.1.4 Invoke Test.main

12.2 Loading of Classes and Interfaces

12.2.1 The Loading Process

12.3 Linking of Classes and Interfaces

12.3.1 Verification of the Binary Representation

12.3.2 Preparation of a Class or Interface Type

12.3.3 Resolution of Symbolic References

12.4 Initialization of Classes and Interfaces

12.4.1 When Initialization Occurs

12.4.2 Detailed Initialization Procedure

12.4.3 Initialization: Implications for Code Generation

12.5 Creation of New Class Instances

12.6 Finalization of Class Instances

12.6.1 Implementing Finalization

12.6.2 Finalizer Invocations are Not Ordered

12.7 Unloading of Classes and Interfaces

12.8 Program Exit

13.1 The Form of a Binary

13.2 What Binary Compatibility Is and Is Not

13.3 Evolution of Packages

13.4 Evolution of Classes

13.4.1 abstract Classes

13.4.2 final Classes

13.4.3 publicClasses

13.4.4 Superclasses and Superinterfaces

13.4.5 Class Body and Member Declarations

13.4.6 Access to Members and Constructors

13.4.7 Field Declarations

13.4.8 final Fields and Constants

13.4.9 static Fields

13.4.10 transient Fields

13.4.11 Method and Constructor Declarations

13.4.12 Method and Constructor Parameters

13.4.13 Method Result Type

13.4.14 abstract Methods

13.4.15 final Methods

13.4.16 native Methods

13.4.17 static Methods

13.4.18 synchronized Methods

13.4.19 Method and Constructor Throws

13.4.20 Method and Constructor Body

13.4.21 Method and Constructor Overloading

13.4.22 Method Overriding

13.4.23 Static Initializers

13.5 Evolution of Interfaces

13.5.1 public Interfaces

13.5.2 Superinterfaces

13.5.3 The Interface Members

13.5.4 Field Declarations

13.5.5 Abstract Method Declarations

14.1 Normal and Abrupt Completion of Statements

14.2 Blocks

14.3 Local Class Declarations

14.4 Local Variable Declaration Statements

14.4.1 Local Variable Declarators and Types

14.4.2 Scope of Local Variable Declarations

14.4.3 Shadowing of Names by Local Variables

14.4.4 Execution of Local Variable Declarations

14.5 Statements

14.6 The Empty Statement

14.7 Labeled Statements

14.8 Expression Statements

14.9 The if Statement

14.9.1 The if-then Statement

14.9.2 The if-then-else Statement

14.10 The switch Statement

14.11 The while Statement

14.11.1 Abrupt Completion

14.12 The do Statement

14.12.1 Abrupt Completion

14.12.2 Example of do statement

14.13 The for Statement

14.13.1 Initialization of for statement

14.13.2 Iteration of for statement

14.13.3 Abrupt Completion of for statement

14.14 The break Statement

14.15 The continue Statement

14.16 The return Statement

14.17 The throw Statement

14.18 The synchronized Statement

14.19 The try statement

14.19.1 Execution of try-catch

14.19.2 Execution of try-catch-finally

14.20 Unreachable Statements

15.1 Evaluation, Denotation, and Result

15.2 Variables as Values

15.3 Type of an Expression

15.4 FP-strict Expressions

15.5 Expressions and Run-Time Checks

15.6 Normal and Abrupt Completion of Evaluation

15.7 Evaluation Order

15.7.1 Evaluate Left-Hand Operand First

15.7.2 Evaluate Operands before Operation

15.7.3 Evaluation Respects Parentheses and Precedence

15.7.4 Argument Lists are Evaluated Left-to-Right

15.7.5 Evaluation Order for Other Expressions

15.8 Primary Expressions

15.8.1 Lexical Literals

15.8.2 Class Literals

15.8.3 this

15.8.4 Qualified this

15.8.5 Parenthesized Expressions

15.9 Class Instance Creation Expressions

15.9.1 Determining the Class being Instantiated

15.9.2 Determining Enclosing Instances

15.9.3 Choosing the Constructor and its Arguments

15.9.4 Run-time Evaluation of Class Instance Creation Expressions

15.9.5 Anonymous Class Declarations

15.9.5.1 Anonymous Constructors

15.9.6 Example: Evaluation Order and Out-of-Memory Detection

15.10 Array Creation Expressions

15.10.1 Run-time Evaluation of Array Creation Expressions

15.10.2 Example: Array Creation Evaluation Order

15.10.3 Example: Array Creation and Out-of-Memory Detection

15.11 Field Access Expressions

15.11.1 Field Access Using a Primary

15.11.2 Accessing Superclass Members using super

15.12 Method Invocation Expressions

15.12.1 Compile-Time Step 1: Determine Class or Interface to Search

15.12.2 Compile-Time Step 2: Determine Method Signature

15.12.2.1 Find Methods that are Applicable and Accessible

15.12.2.2 Choose the Most Specific Method

15.12.2.3 Example: Overloading Ambiguity

15.12.2.4 Example: Return Type Not Considered

15.12.2.5 Example: Compile-Time Resolution

15.12.3 Compile-Time Step 3: Is the Chosen Method Appropriate?

15.12.4 Runtime Evaluation of Method Invocation

15.12.4.1 Compute Target Reference (If Necessary)

15.12.4.2 Evaluate Arguments

15.12.4.3 Check Accessibility of Type and Method

15.12.4.4 Locate Method to Invoke

15.12.4.5 Create Frame, Synchronize, Transfer Control

15.12.4.6 Example: Target Reference and Static Methods

15.12.4.7 Example: Evaluation Order

15.12.4.8 Example: Overriding

15.12.4.9 Example: Method Invocation using super

15.13 Array Access Expressions

15.13.1 Runtime Evaluation of Array Access

15.13.2 Examples: Array Access Evaluation Order

15.14 Postfix Expressions

15.14.1 Postfix Increment Operator ++

15.14.2 Postfix Decrement Operator --

15.15 Unary Operators

15.15.1 Prefix Increment Operator ++

15.15.2 Prefix Decrement Operator --

15.15.3 Unary Plus Operator +

15.15.4 Unary Minus Operator -

15.15.5 Bitwise Complement Operator ~

15.15.6 Logical Complement Operator !

15.16 Cast Expressions

15.17 Multiplicative Operators

15.17.1 Multiplication Operator *

15.17.2 Division Operator /

15.17.3 Remainder Operator %

15.18 Additive Operators

15.18.1 String Concatenation Operator +

15.18.1.1 String Conversion

15.18.1.2 Optimization of String Concatenation

15.18.1.3 Examples of String Concatenation

15.18.2 Additive Operators (+ and -) for Numeric Types

15.19 Shift Operators

15.20 Relational Operators

15.20.1 Numerical Comparison Operators <, <=, >, and >=

15.20.2 Type Comparison Operator instanceof

15.21 Equality Operators

15.21.1 Numerical Equality Operators == and !=

15.21.2 Boolean Equality Operators == and !=

15.21.3 Reference Equality Operators == and !=

15.22 Bitwise and Logical Operators

15.22.1 Integer Bitwise Operators &, ^, and |

15.22.2 Boolean Logical Operators &, ^, and |

15.23 Conditional-And Operator &&

15.24 Conditional-Or Operator ||

15.25 Conditional Operator ? :

15.26 Assignment Operators

15.26.1 Simple Assignment Operator =

15.26.2 Compound Assignment Operators

15.27 Expression

15.28 Constant Expression

16.1 Definite Assignment and Expressions

16.1.1 Boolean Constant Expressions

16.1.2 The Boolean Operator &&

16.1.3 The Boolean Operator ||

16.1.4 The Boolean Operator !

16.1.5 The Boolean Operator ? :

16.1.6 The Conditional Operator ? :

16.1.7 Assignment Expressions

16.1.8 Operators ++ and --

16.1.9 Other Expressions

16.2 Definite Assignment and Statements

16.2.1 Empty Statements

16.2.2 Blocks

16.2.3 Local Class Declaration Statements

16.2.4 Local Variable Declaration Statements

16.2.5 Labeled Statements

16.2.6 Expression Statements

16.2.7 if Statements

16.2.8 switch Statements

16.2.9 while Statements

16.2.10 do Statements

16.2.11 for Statements

16.2.11.1 Initialization Part

16.2.11.2 Incrementation Part

16.2.12 break, continue, return, and throw Statements

16.2.13 synchronized Statements

16.2.14 try Statements

16.3 Definite Assignment and Parameters

16.4 Definite Assignment and Array Initializers

16.5 Definite Assignment and Anonymous Classes

16.6 Definite Assignment and Member Types

16.7 Definite Assignment and Static Initializers

16.8 Definite Assignment, Constructors, and Instance Initializers

17.1 Terminology and Framework

17.2 Execution Order

17.3 Rules about Variables

17.4 Nonatomic Treatment of double and long

17.5 Rules about Locks

17.6 Rules about the Interaction of Locks and Variables

17.7 Rules for Volatile Variables

17.8 Prescient Store Actions

17.9 Discussion

17.10 Example: Possible Swap

17.11 Example: Out-of-Order Writes

17.12 Threads

17.13 Locks and Synchronization

17.14 Wait Sets and Notification

18.1 The Grammar of the Java Programming Language

Index