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Java Pocket Guide, 4th Edition

by Robert Liguori, Patricia Liguori

August 2017

Intermediate to advanced

290 pages

4h 10m

English

O'Reilly Media, Inc.

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Book StructureConventions Used in This BookO’Reilly SafariHow to Contact UsAcknowledgments
AcronymsAnnotation NamesClass NamesConstant NamesEnumeration NamesGeneric Type Parameter NamesInstance and Static Variable NamesInterface NamesMethod NamesPackage NamesModule NamesParameter and Local Variable Names
Unicode and ASCIIPrintable ASCII CharactersNonprintable ASCII CharactersCompact StringsCommentsKeywordsIdentifiersSeparatorsOperatorsLiteralsBoolean LiteralsCharacter LiteralsInteger LiteralsFloating-Point LiteralsString LiteralsNull LiteralsEscape SequencesUnicode Currency Symbols
Primitive TypesLiterals for Primitive TypesFloating-Point EntitiesOperations Involving Special EntitiesNumeric Promotion of Primitive TypesUnary Numeric PromotionBinary Numeric PromotionSpecial Cases for Conditional OperatorsWrapper ClassesAutoboxing and UnboxingAutoboxingUnboxing
Comparing Reference Types to Primitive TypesDefault ValuesInstance and Local Variable ObjectsArraysConversion of Reference TypesWidening ConversionsNarrowing ConversionsConverting Between Primitives and Reference TypesPassing Reference Types into MethodsComparing Reference TypesUsing the Equality OperatorsUsing the equals() MethodComparing StringsComparing EnumerationsCopying Reference TypesCopying a Reference to an ObjectCloning ObjectsMemory Allocation and Garbage Collection of Reference Types
Classes and ObjectsClass SyntaxInstantiating a Class (Creating an Object)Data Members and MethodsAccessing Data Members and Methods in ObjectsOverloadingOverridingConstructorsSuperclasses and SubclassesThe this KeywordVariable-Length Argument ListsAbstract Classes and Abstract MethodsAbstract ClassesAbstract MethodsStatic Data Members, Static Methods, Static Constants, and Static InitializersStatic Data MembersStatic MethodsStatic ConstantsStatic InitializersInterfacesEnumerationsAnnotation TypesBuilt-in AnnotationsDeveloper-Defined AnnotationsFunctional Interfaces
Expression StatementsEmpty StatementBlocksConditional StatementsThe if StatementThe if else StatementThe if else if StatementThe switch StatementIteration StatementsThe for LoopThe Enhanced for LoopThe while LoopThe do while LoopTransfer of ControlThe break StatementThe continue StatementThe return StatementSynchronized StatementAssert StatementException Handling Statements
The Exception HierarchyChecked/Unchecked Exceptions and ErrorsChecked ExceptionsUnchecked ExceptionsErrorsCommon Checked/Unchecked Exceptions and ErrorsCommon Checked ExceptionsCommon Unchecked ExceptionsCommon ErrorsException Handling KeywordsThe throw KeywordThe try/catch/finally KeywordsThe try-catch StatementThe try-finally StatementThe try-catch-finally StatementThe try-with-resources StatementThe multi-catch ClauseThe Exception Handling ProcessDefining Your Own Exception ClassPrinting Information About ExceptionsThe getMessage() MethodThe toString() MethodThe printStackTrace() Method
Access ModifiersOther (Nonaccess) ModifiersModifiers Encoding

Common Java SE API LibrariesLanguage and Utility LibrariesBase LibrariesIntegration LibrariesMiscellaneous User Interface LibrariesJavaFX User Interface LibraryRemote Method Invocation (RMI) and CORBA LibrariesSecurity LibrariesExtensible Markup Language (XML) Libraries
Java Runtime EnvironmentJava Development KitJava Program StructureCommand-Line ToolsJava CompilerJava InterpreterJava Program PackagerJAR File ExecutionClasspath
Garbage CollectorsSerial CollectorParallel CollectorParallel Compacting CollectorConcurrent Mark-Sweep CollectorGarbage-First (G1) CollectorMemory Management ToolsCommand-Line OptionsResizing the JVM HeapMetaspaceInterfacing with the GCExplicit Garbage CollectionFinalization
Standard Streams in, out, and errClass Hierarchy for Basic Input and OutputFile Reading and WritingReading Character Data from a FileReading Binary Data from a FileWriting Character Data to a FileWriting Binary Data to a FileSocket Reading and WritingReading Character Data from a SocketReading Binary Data from a SocketWriting Character Data to a SocketWriting Binary Data to a SocketSerializationSerializeDeserializeZipping and Unzipping FilesCompressing and Uncompressing GZIP Files
The Path InterfaceThe Files ClassAdditional Features
Creating ThreadsExtending the Thread ClassImplementing the Runnable InterfaceThread StatesThread PrioritiesCommon MethodsSynchronizationConcurrent UtilitiesExecutorsConcurrent CollectionsSynchronizersTiming Utility
The Collection InterfaceImplementationsCollection Framework MethodsCollections Class AlgorithmsAlgorithm EfficienciesComparator Functional InterfaceConvenience Factory Methods
Generic Classes and InterfacesConstructors with GenericsSubstitution PrincipleType Parameters, Wildcards, and BoundsThe Get and Put PrincipleGeneric SpecializationGeneric Methods in Raw Types
Scripting LanguagesScript Engine ImplementationsEmbedding Scripts into JavaInvoking Methods of Scripting LanguagesAccessing and Controlling Java Resources from ScriptsSetting Up Scripting Languages and EnginesScripting Language SetupScripting Engine SetupScripting Engine Validation
Legacy InteroperabilityRegional CalendarsISO CalendarMachine InterfaceDurations and PeriodsJDBC and XSD MappingFormatting
λEs BasicsλEs Syntax and ExampleMethod and Constructor ReferencesSpecific-Purpose Functional InterfacesGeneral-Purpose Functional InterfacesResources for λEsTutorialsCommunity Resources
Getting StartedSnippetsModifiersFlow Control StatementsPackage DeclarationsUsing JShellPrimary ExpressionsDependenciesStatements and Code BlocksMethod and Class DeclarationsViewing, Deleting, and Modifying SnippetsSaving, Loading, and StateJShell FeaturesScratch VariablesTab Auto-CompleteForward ReferencingChecked ExceptionsHierarchy and ScopeSummary of JShell Commands
Project JigsawJava ModulesAutomatic ModulesUnnamed ModulesAccessibilityCompiling ModulesModular JDKjdepsIdentifying DependenciesIdentifying Undocumented JDK Internal DependenciesDefining a ModuleExporting a PackageDeclaring DependenciesTransitive DependenciesDefining Service ProvidersDefining Service APIImplementing Service APIUsing Service Providersjlink
Development, CM, and Test ToolsLibrariesIntegrated Development EnvironmentsWeb Application PlatformsScripting Languages Compatible with JSR-223
Class DiagramsNameAttributesOperationsVisibilityObject DiagramsGraphical Icon RepresentationClasses, Abstract Classes, and InterfacesNotesPackagesConnectorsMultiplicity IndicatorsRole NamesClass RelationshipsAssociationDirect AssociationComposition AssociationAggregation AssociationTemporary AssociationGeneralizationRealizationSequence DiagramsParticipant (1)Found Message (2)Synchronous Message (3)Return Call (4)Asynchronous Message (5)Message to Self (6)Lifeline (7)Activation Bar (8)

Content preview from Java Pocket Guide, 4th Edition

Chapter 11. Memory Management

Java has automatic memory management, which is also known as garbage collection (GC). GC’s principal tasks are allocating memory, maintaining referenced objects in memory, and recovering memory from objects that no longer have references to them.

Garbage Collectors

Since the J2SE 5.0 release, the Java HotSpot Virtual Machine performs self-tuning. This process includes the attempted best-fit GC and related settings at startup, based on platform information, as well as ongoing GC tuning.

Although the initial settings and runtime tuning for GC are generally successful, there are times when you may wish to change or tune your GC based on the following goals:

Maximum pause time goal: The maximum pause time goal is the desired time that the GC pauses the application to recover memory.
Throughput goal: The throughput goal is the desired application time, or the time spent outside of GC.

The following sections provide an overview of various garbage collectors, their main focus, and situations in which they should be used. “Command-Line Options” explains how to acquire information for manually selecting the GC.

Serial Collector

The serial collector is performed via a single thread on a single CPU. When this GC thread is run, the execution of the application will pause until the collection is complete.

This collection is best used when your application has a small data set, up to approximately 100 MB, and does not have a requirement for low pause times. ...