Feature Map

This document maps each Java release to the example and test classes that demonstrate or document its features.

Use this when you already know the Java version or feature name and want to jump directly to the code. For learning context, open the linked version README first. For release chronology, use java-release-timeline.md. For feature maturity and JEP links, use status-matrix.md. For a shorter list of hands-on demonstrations, use practical-demos.md.

Java 1

Learning notes: java01 README

Feature	Example	Test
Object-oriented basics	`ObjectOrientedBasicsExamples`	`ObjectOrientedBasicsExamplesTest`
Interfaces	`InterfaceExamples`	`InterfaceExamplesTest`
Checked exceptions	`ExceptionHandlingBasicsExamples`	`ExceptionHandlingBasicsExamplesTest`
Threads and Runnable	`ThreadBasicsExamples`	`ThreadBasicsExamplesTest`
`java.io` streams	`IoBasicsExamples`	`IoBasicsExamplesTest`
Inner classes	`InnerClassExamples`	`InnerClassExamplesTest`
Reflection	`reflection/ReflectionExamples`	`ReflectionExamplesTest`
Serialization	`serialization/SerializationExamples`	`SerializationExamplesTest`
JDBC	`jdbc/JdbcExamples`	`JdbcExamplesTest`
RMI	`rmi/RmiExamples`	`RmiExamplesTest`
JavaBeans	`javabeans/JavaBeansExamples`	`JavaBeansExamplesTest`

Java 2

Learning notes: java02 README

Feature	Example	Test
Collections Framework	`CollectionsFrameworkExamples`	`CollectionsFrameworkExamplesTest`
Sorting with `Comparable` and `Comparator`	`SortingExamples`	`SortingExamplesTest`
`strictfp`	`strict_floating_point/StrictFloatingPointExamples`	`StrictFloatingPointExamplesTest`
Swing	`swing/SwingExamples`	`SwingExamplesTest`
Java 2D	`java2d/Java2DExamples`	`Java2DExamplesTest`
Security policy	`security/SecurityPolicyExamples`	`SecurityPolicyExamplesTest`

Java 3

Learning notes: java03 README

Feature	Example	Test
Dynamic proxy	`DynamicProxyExamples`	`DynamicProxyExamplesTest`
Timer and TimerTask	`TimerExamples`	`TimerExamplesTest`
Shutdown hooks	`shutdown_hooks/ShutdownHookExamples`	`ShutdownHookExamplesTest`
JNDI	`jndi/JndiExamples`	`JndiExamplesTest`
Legacy integration	`legacy_integration/LegacyIntegrationNotes`	`LegacyIntegrationNotesTest`

Java 4

Learning notes: java04 README

Feature	Example	Test
Assertions	`assertions/AssertionExamples`	`AssertionExamplesTest`
Regular expressions	`RegexExamples`	`RegexExamplesTest`
NIO	`NioExamples`	`NioExamplesTest`
Logging API	`LoggingExamples`	`LoggingExamplesTest`
Chained exceptions	`ChainedExceptionExamples`	`ChainedExceptionExamplesTest`
Preferences API	`preferences/PreferencesNotes`	`PreferencesNotesTest`
XML/JAXP	`xml/JaxpExamples`	`JaxpExamplesTest`
Integrated security APIs	`security/SecurityIntegrationExamples`	`SecurityIntegrationExamplesTest`

Java 5

Learning notes: java05 README

Feature	Example	Test
Generics	`GenericsExamples`	`GenericsExamplesTest`
Enhanced for loop	`EnhancedForLoopExamples`	`EnhancedForLoopExamplesTest`
Autoboxing and unboxing	`AutoboxingExamples`	`AutoboxingExamplesTest`
Typesafe enums	`EnumExamples`	`EnumExamplesTest`
Varargs	`VarargsExamples`	`VarargsExamplesTest`
Static import	`StaticImportExamples`	`StaticImportExamplesTest`
Annotations	`AnnotationExamples`	`AnnotationExamplesTest`
Covariant return types	`CovariantReturnExamples`	`CovariantReturnExamplesTest`
Formatted output	`FormattingExamples`	`FormattingExamplesTest`
Concurrency utilities	`ConcurrencyUtilitiesExamples`	`ConcurrencyUtilitiesExamplesTest`

Java 6

Learning notes: java06 README

Feature	Example	Test
Navigable collections and deques	`NavigableCollectionExamples`	`NavigableCollectionExamplesTest`
Scripting support	`scripting/ScriptingSupportExamples`	`ScriptingSupportExamplesTest`
Compiler API	`compiler_api/CompilerApiExamples`	`CompilerApiExamplesTest`
Console API	`console_api/ConsoleApiExamples`	`ConsoleApiExamplesTest`
Monitoring and management	`monitoring_management/MonitoringManagementExamples`	`MonitoringManagementExamplesTest`
Web-service support	`web_services/WebServiceSupportNotes`	`WebServiceSupportNotesTest`

Java 7

Learning notes: java07 README

Feature	Example	Test
Try-with-resources	`TryWithResourcesStatementExamples`	`TryWithResourcesStatementExamplesTest`
Multi-catch and precise rethrow	`ExceptionHandlingExamples`	`ExceptionHandlingExamplesTest`
Diamond operator	`DiamondOperatorExamples`	`DiamondOperatorExamplesTest`
Strings in switch	`StringSwitchExamples`	`StringSwitchExamplesTest`
Binary literals and numeric underscores	`NumericLiteralExamples`	`NumericLiteralExamplesTest`
NIO.2	`Nio2Examples`	`Nio2ExamplesTest`
Fork/join framework	`ForkJoinExamples`	`ForkJoinExamplesTest`
`invokedynamic`	`invokedynamic/InvokeDynamicExamples`	`InvokeDynamicExamplesTest`

Java 8

Learning notes: java08 README

Feature	Example	Test
Lambdas	`LambdaExamples`	`LambdaExamplesTest`
Streams	`StreamExamples`	`StreamExamplesTest`
Optional	`OptionalExamples`	`OptionalExamplesTest`
Method references	`MethodReferenceExamples`	`MethodReferenceExamplesTest`
CompletableFuture	`CompletableFutureExamples`	`CompletableFutureExamplesTest`
Default methods	`DefaultMethodExamples`	`DefaultMethodExamplesTest`
Date/Time API	`DateTimeApiExamples`	`DateTimeApiExamplesTest`

Java 9

Learning notes: java09 README

Feature	Example	Test
Collection factories	`CollectionFactoryExamples`	`CollectionFactoryExamplesTest`
Optional enhancements	`OptionalEnhancementExamples`	`OptionalEnhancementExamplesTest`
Stream enhancements	`StreamEnhancementExamples`	`StreamEnhancementExamplesTest`
Private interface methods	`PrivateInterfaceMethodExamples`	`PrivateInterfaceMethodExamplesTest`
Try-with-resources improvement	`TryWithResourcesExamples`	`TryWithResourcesExamplesTest`
Process API	`ProcessApiExamples`	`ProcessApiExamplesTest`
StackWalker	`StackWalkerExamples`	`StackWalkerExamplesTest`
Module system	`ModuleSystemExamples`	`ModuleSystemExamplesTest`

Java 10

Learning notes: java10 README

Feature	Example	Test
Local variable type inference	`LocalVariableTypeInferenceExamples`	`LocalVariableTypeInferenceExamplesTest`
Unmodifiable collectors	`UnmodifiableCollectorsExamples`	`UnmodifiableCollectorsExamplesTest`
`Optional.orElseThrow()`	`OptionalOrElseThrowExamples`	`OptionalOrElseThrowExamplesTest`

Java 11

Learning notes: java11 README

Feature	Example	Test
String API additions	`StringApiExamples`	`StringApiExamplesTest`
Files read/write string	`FilesApiExamples`	`FilesApiExamplesTest`
HTTP Client	`HttpClientExamples`	`HttpClientExamplesTest`
`Predicate.not`	`PredicateNotExamples`	`PredicateNotExamplesTest`
Lambda `var`	`LambdaVarExamples`	`LambdaVarExamplesTest`
`Optional.isEmpty`	`OptionalIsEmptyExamples`	`OptionalIsEmptyExamplesTest`

Java 12

Learning notes: java12 README

Feature	Example	Test
Switch expressions preview	`SwitchExpressionPreviewExamples`	`SwitchExpressionPreviewExamplesTest`
Teeing collector	`TeeingCollectorExamples`	`TeeingCollectorExamplesTest`
`String.indent`	`StringIndentExamples`	`StringIndentExamplesTest`
`Files.mismatch`	`FilesMismatchExamples`	`FilesMismatchExamplesTest`
Compact number formatting	`CompactNumberFormatExamples`	`CompactNumberFormatExamplesTest`

Java 13

Learning notes: java13 README

Feature	Example	Test
Text blocks preview	`TextBlockPreviewExamples`	`TextBlockPreviewExamplesTest`
Switch `yield` preview	`SwitchYieldPreviewExamples`	`SwitchYieldPreviewExamplesTest`
`FileSystems.newFileSystem(Path)`	`FileSystemsNewFileSystemExamples`	`FileSystemsNewFileSystemExamplesTest`

Java 14

Learning notes: java14 README

Feature	Example	Test
Switch expressions final	`SwitchExpressionExamples`	`SwitchExpressionExamplesTest`
Helpful NullPointerExceptions	`HelpfulNullPointerExceptionExamples`	`HelpfulNullPointerExceptionExamplesTest`
Records preview	`RecordPreviewExamples`	`RecordPreviewExamplesTest`
Pattern matching for `instanceof` preview	`PatternMatchingInstanceofPreviewExamples`	`PatternMatchingInstanceofPreviewExamplesTest`

Java 15

Learning notes: java15 README

Feature	Example	Test
Text blocks final	`TextBlockExamples`	`TextBlockExamplesTest`
Sealed classes preview	`SealedClassesPreviewExamples`	`SealedClassesPreviewExamplesTest`
Hidden classes	`HiddenClassesExamples`	`HiddenClassesExamplesTest`

Java 16

Learning notes: java16 README

Feature	Example	Test
Records final	`RecordExamples`	`RecordExamplesTest`
Pattern matching for `instanceof` final	`PatternMatchingInstanceofExamples`	`PatternMatchingInstanceofExamplesTest`
`Stream.toList()`	`StreamToListExamples`	`StreamToListExamplesTest`
Unix-domain socket channels	`unix_domain_socket/UnixDomainSocketChannelExamples`	`UnixDomainSocketChannelExamplesTest`
Vector API first incubator	java16 README	No dedicated test
Foreign Linker API incubator	java16 README	No dedicated test
Foreign-Memory Access API third incubator	java16 README	No dedicated test

Java 17

Learning notes: java17 README

Feature	Example	Test
Sealed classes final	`SealedClassesExamples`	`SealedClassesExamplesTest`
Pattern matching for switch preview	`PatternMatchingSwitchPreviewExamples`	`PatternMatchingSwitchPreviewExamplesTest`
Random Generator API	`RandomGeneratorExamples`	`RandomGeneratorExamplesTest`
`HexFormat`	`HexFormatExamples`	`HexFormatExamplesTest`
Strong encapsulation	`strong_encapsulation/StrongEncapsulationExamples`	`StrongEncapsulationExamplesTest`

Java 18

Learning notes: java18 README

Feature	Example	Test
UTF-8 default charset	`Utf8DefaultCharsetExamples`	`Utf8DefaultCharsetExamplesTest`
Simple Web Server	`SimpleStaticFileServer`	`SimpleStaticFileServerTest`
JavaDoc snippets	`JavaDocSnippetExamples`	`JavaDocSnippetExamplesTest`
Internet-Address Resolution SPI	`inet_address_resolution/InetAddressResolutionExamples`	`InetAddressResolutionExamplesTest`

Java 19

Learning notes: java19 README

Feature	Example	Test
Virtual threads preview	`VirtualThreadsPreviewExamples`	`VirtualThreadsPreviewExamplesTest`
Record patterns preview	`RecordPatternsPreviewExamples`	`RecordPatternsPreviewExamplesTest`
Pattern matching for switch preview	`PatternMatchingSwitchPreviewExamples`	`PatternMatchingSwitchPreviewExamplesTest`
Structured concurrency incubator	`StructuredConcurrencyPreviewNotes`	`StructuredConcurrencyPreviewNotesTest`
Foreign Function and Memory API	`ForeignFunctionMemoryApiPreviewNotes`	`ForeignFunctionMemoryApiPreviewNotesTest`

Java 20

Learning notes: java20 README

Feature	Example	Test
Record patterns second preview	`RecordPatternsSecondPreviewExamples`	`RecordPatternsSecondPreviewExamplesTest`
Pattern matching for switch fourth preview	`PatternMatchingSwitchFourthPreviewExamples`	`PatternMatchingSwitchFourthPreviewExamplesTest`
Virtual threads second preview	`VirtualThreadsSecondPreviewNotes`	`VirtualThreadsSecondPreviewNotesTest`
Scoped values incubator	`ScopedValuesIncubatorNotes`	`ScopedValuesIncubatorNotesTest`
Structured concurrency second incubator	`StructuredConcurrencySecondIncubatorNotes`	`StructuredConcurrencySecondIncubatorNotesTest`
Foreign Function and Memory API second preview	`ForeignFunctionMemorySecondPreviewNotes`	`ForeignFunctionMemorySecondPreviewNotesTest`
Vector API fifth incubator	`VectorApiFifthIncubatorExamples`	`VectorApiFifthIncubatorExamplesTest`

Java 21

Learning notes: java21 README

Feature	Example	Test
Virtual threads final	`VirtualThreadsExamples`	`VirtualThreadsExamplesTest`
Record patterns final	`RecordPatternsExamples`	`RecordPatternsExamplesTest`
Pattern matching for switch final	`PatternMatchingSwitchExamples`	`PatternMatchingSwitchExamplesTest`
Sequenced collections final	`SequencedCollectionsExamples`	`SequencedCollectionsExamplesTest`
Unnamed patterns and variables preview	`UnnamedPatternsVariablesPreviewExamples`	`UnnamedPatternsVariablesPreviewExamplesTest`
Key Encapsulation Mechanism API	`KeyEncapsulationExchange`	`KeyEncapsulationExchangeTest`
Scoped values preview	`ScopedValuesPreviewNotes`	`ScopedValuesPreviewNotesTest`
Structured concurrency preview	`StructuredConcurrencyPreviewNotes`	`StructuredConcurrencyPreviewNotesTest`

Java 22

Learning notes: java22 README

Feature	Example	Test
Unnamed variables and patterns final	`UnnamedVariablesPatternsExamples`	`UnnamedVariablesPatternsExamplesTest`
Statements before `super(...)` preview	`StatementsBeforeSuperPreviewNotes`	`StatementsBeforeSuperPreviewNotesTest`
Stream Gatherers preview	`StreamGatherersPreviewNotes`	`StreamGatherersPreviewNotesTest`
Foreign Function and Memory API final	`NativeStringParser`, `NativeStringLength`	`ForeignFunctionExamplesTest`
Multi-file source launcher final	`LaunchMultiFileSourceProgramsExamples`	`LaunchMultiFileSourceProgramsExamplesTest`
Class-File API preview	`ClassFileApiPreviewNotes`	`ClassFileApiPreviewNotesTest`
Scoped values second preview	`ScopedValuesSecondPreviewNotes`	`ScopedValuesSecondPreviewNotesTest`
Structured concurrency second preview	`StructuredConcurrencySecondPreviewNotes`	`StructuredConcurrencySecondPreviewNotesTest`

Java 23

Learning notes: java23 README

Feature	Example	Test
Markdown documentation comments	`MarkdownDocumentationCommentsExamples`	`MarkdownDocumentationCommentsExamplesTest`
Primitive patterns preview	`PrimitivePatternsPreviewNotes`	`PrimitivePatternsPreviewNotesTest`
Module import declarations preview	`ModuleImportDeclarationsPreviewNotes`	`ModuleImportDeclarationsPreviewNotesTest`
Flexible constructor bodies second preview	`FlexibleConstructorBodiesSecondPreviewNotes`	`FlexibleConstructorBodiesSecondPreviewNotesTest`
Stream Gatherers second preview	`StreamGatherersSecondPreviewNotes`	`StreamGatherersSecondPreviewNotesTest`
Class-File API second preview	`ClassFileApiSecondPreviewNotes`	`ClassFileApiSecondPreviewNotesTest`
Scoped values third preview	`ScopedValuesThirdPreviewNotes`	`ScopedValuesThirdPreviewNotesTest`
Structured concurrency third preview	`StructuredConcurrencyThirdPreviewNotes`	`StructuredConcurrencyThirdPreviewNotesTest`
Unsafe memory-access deprecation	`UnsafeMemoryAccessDeprecationExamples`	`UnsafeMemoryAccessDeprecationExamplesTest`
ZGC generational mode	`ZgcGenerationalModeExamples`	`ZgcGenerationalModeExamplesTest`

Java 24

Learning notes: java24 README

Feature	Example	Test
Stream Gatherers final	`StreamGatherersExamples`	`StreamGatherersExamplesTest`
Class-File API final	`ClassFileInspector`	`ClassFileInspectorTest`
Security Manager disabled	`SecurityManagerDisabledExamples`	`SecurityManagerDisabledExamplesTest`
Virtual-thread synchronization	`VirtualThreadSynchronizationExamples`	`VirtualThreadSynchronizationExamplesTest`
Quantum-resistant crypto	`ModuleLatticeKemExample`, `ModuleLatticeDsaExample`	`ModuleLatticeCryptoExamplesTest`
AOT class loading	`AotClassLoadingExamples`	`AotClassLoadingExamplesTest`
KDF preview	`KeyDerivationFunctionPreviewNotes`	`KeyDerivationFunctionPreviewNotesTest`
Flexible constructor bodies third preview	`FlexibleConstructorBodiesThirdPreviewNotes`	`FlexibleConstructorBodiesThirdPreviewNotesTest`
Module import declarations second preview	`ModuleImportDeclarationsSecondPreviewNotes`	`ModuleImportDeclarationsSecondPreviewNotesTest`
Primitive patterns second preview	`PrimitivePatternsSecondPreviewNotes`	`PrimitivePatternsSecondPreviewNotesTest`
Scoped values fourth preview	`ScopedValuesFourthPreviewNotes`	`ScopedValuesFourthPreviewNotesTest`
Structured concurrency fourth preview	`StructuredConcurrencyFourthPreviewNotes`	`StructuredConcurrencyFourthPreviewNotesTest`

Java 25

Learning notes: java25 README

Feature	Example	Test
Scoped values final	`ScopedValuesExamples`	`ScopedValuesExamplesTest`
Flexible constructor bodies final	`FlexibleConstructorBodiesExamples`	`FlexibleConstructorBodiesExamplesTest`
Module import declarations final	`ModuleImportDeclarationsExamples`	`ModuleImportDeclarationsExamplesTest`
Compact source files final	`CompactSourceFilesExamples`	`CompactSourceFilesExamplesTest`
Key Derivation Function API final	`HkdfKeyDerivationExample`	`HkdfKeyDerivationExampleTest`
Primitive patterns third preview	`PrimitivePatternsThirdPreviewExamples`	`PrimitivePatternsThirdPreviewExamplesTest`
Stable values preview	`StableValuesPreviewExamples`	`StableValuesPreviewExamplesTest`
PEM encodings preview	`PemEncodingsPreviewExamples`	`PemEncodingsPreviewExamplesTest`
Structured concurrency fifth preview	`StructuredConcurrencyFifthPreviewExamples`	`StructuredConcurrencyFifthPreviewExamplesTest`
Vector API tenth incubator	`VectorApiTenthIncubatorExamples`	`VectorApiTenthIncubatorExamplesTest`
AOT command-line ergonomics	`AotCommandLineErgonomicsExamples`	`AotCommandLineErgonomicsExamplesTest`
JFR enhancements	`JfrEnhancementsExamples`	`JfrEnhancementsExamplesTest`
Compact object headers	`CompactObjectHeadersExamples`	`CompactObjectHeadersExamplesTest`
Generational Shenandoah	`GenerationalShenandoahNotes`	`GenerationalShenandoahNotesTest`

Java 26

Learning notes: java26 README

Java 26 is represented as C2 explanatory material while the repository keeps JDK 25 as its build baseline.

Feature	Example	Test
HTTP/3 for the HTTP Client API	`Http3ClientNotes`	`Http3ClientNotesTest`
Final field restrictions	`FinalFieldRestrictionsNotes`	`FinalFieldRestrictionsNotesTest`
Applet API removal	`AppletApiRemovalNotes`	`AppletApiRemovalNotesTest`
AOT object caching	`AotObjectCachingNotes`	`AotObjectCachingNotesTest`
G1 synchronization reduction	`G1SynchronizationNotes`	`G1SynchronizationNotesTest`
PEM encodings second preview	`PemEncodingsSecondPreviewNotes`	`PemEncodingsSecondPreviewNotesTest`
Structured concurrency sixth preview	`StructuredConcurrencySixthPreviewNotes`	`StructuredConcurrencySixthPreviewNotesTest`
Lazy Constants second preview	`LazyConstantsSecondPreviewNotes`	`LazyConstantsSecondPreviewNotesTest`
Vector API eleventh incubator	`VectorApiEleventhIncubatorNotes`	`VectorApiEleventhIncubatorNotesTest`
Primitive patterns fourth preview	`PrimitivePatternsFourthPreviewNotes`	`PrimitivePatternsFourthPreviewNotesTest`

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