Some Classes with a public void close() don't implement AutoCloseable

[Remi Forax]

interface FakeAutoCloseable extends AutoCloseable { public void close(); }  // suppress exception

XMLReader xmlReader = ...
try(FakeAutoCloseable __ = xmlReader::close) {
  ...
}

Rémi

----- Mail original -----
> De: "Johannes Kuhn" <info at j-kuhn.de>
> À: "discuss" <discuss at openjdk.java.net>
> Envoyé: Mercredi 15 Avril 2020 15:35:38
> Objet: Some Classes with a public void close() don't implement AutoCloseable

> Hi,
> 
> After failing to wrap a XMLStreamReader in a try-with-resources after
> discovering it's close() method,
> I thought about checking what other classes have a public void close()
> method in the JDK but don't implement AutoCloseable.
> 
> For this reason I wrote a small program that enumerates all classes
> present in in my jrt image with a public void close() method that does not
> directly or indirectly implement AutoCloseable:
> https://gist.github.com/DasBrain/8d50e02e35654870e2c2c00bf3f79954
> (Output & Code, Code requires JDK 14 with preview features and ASM)
> 
> As I am not an expert in any of those areas, I don't know if that was
> just an oversight or intended.
> 
> The XMLStreamReaderImpl will just set a flag to indicate that this
> instance can be reused, with a comment //xxx: Check what this function
> is intended to do.
> The most likely candidate for adding AutoCloseable is
> javax.naming.Context in my opinion.
> Not sure about java.util.logging.Handler. As far as I know those are
> closed by the Logger and closed when reloading the configuration for
> example.
> 
> Anyway, thought I share this. We could maybe add a few implements
> AutoCloseable or add some comments why they don't implement that.
> Some IDEs rely on resource leak warnings on the interface, so adding the
> interface can be double edged sword.
> 
> With best regards,
> Johannes Kuhn
> 
> Output:
> com/sun/jdi/connect/spi/Connection
> com/sun/jndi/dns/BaseNameClassPairEnumeration
> com/sun/jndi/dns/DnsClient
> com/sun/jndi/dns/DnsContext
> com/sun/jndi/dns/Resolver
> com/sun/jndi/ldap/AbstractLdapNamingEnumeration
> com/sun/jndi/ldap/LdapCtx
> com/sun/jndi/ldap/LdapReferralContext
> com/sun/jndi/ldap/LdapSchemaCtx
> com/sun/jndi/ldap/ext/StartTlsResponseImpl
> com/sun/jndi/rmi/registry/BindingEnumeration
> com/sun/jndi/rmi/registry/NameClassPairEnumeration
> com/sun/jndi/rmi/registry/RegistryContext
> com/sun/jndi/toolkit/dir/ContextEnumerator
> com/sun/jndi/toolkit/dir/HierMemDirCtx
> com/sun/jndi/toolkit/dir/HierMemDirCtx$BaseFlatNames
> com/sun/jndi/toolkit/dir/LazySearchEnumerationImpl
> com/sun/jndi/toolkit/url/GenericURLContext
> com/sun/media/sound/AudioFloatFormatConverter$AudioFloatInputStreamChannelMixer
> com/sun/media/sound/AudioFloatFormatConverter$AudioFloatInputStreamResampler
> com/sun/media/sound/AudioFloatInputStream
> com/sun/media/sound/AudioFloatInputStream$BytaArrayAudioFloatInputStream
> com/sun/media/sound/AudioFloatInputStream$DirectAudioFloatInputStream
> com/sun/media/sound/ModelAbstractOscillator
> com/sun/media/sound/ModelDirector
> com/sun/media/sound/ModelOscillatorStream
> com/sun/media/sound/ModelStandardDirector
> com/sun/media/sound/ModelStandardIndexedDirector
> com/sun/media/sound/RIFFWriter$RandomAccessByteWriter
> com/sun/media/sound/RIFFWriter$RandomAccessFileWriter
> com/sun/media/sound/RIFFWriter$RandomAccessWriter
> com/sun/media/sound/SoftAbstractResampler$ModelAbstractResamplerStream
> com/sun/media/sound/SoftMainMixer
> com/sun/media/sound/SoftMixingDataLine$AudioFloatInputStreamResampler
> com/sun/media/sound/SoftMixingMainMixer
> com/sun/media/sound/SoftMixingSourceDataLine$NonBlockingFloatInputStream
> com/sun/naming/internal/VersionHelper$InputStreamEnumeration
> com/sun/org/apache/xerces/internal/impl/XMLStreamFilterImpl
> com/sun/org/apache/xerces/internal/impl/XMLStreamReaderImpl
> com/sun/org/apache/xerces/internal/xinclude/XIncludeTextReader
> com/sun/org/apache/xml/internal/serializer/EmptySerializer
> com/sun/org/apache/xml/internal/serializer/SerializationHandler
> com/sun/org/apache/xml/internal/serializer/SerializerBase
> com/sun/org/apache/xml/internal/serializer/ToHTMLSAXHandler
> com/sun/org/apache/xml/internal/serializer/ToUnknownStream
> com/sun/org/apache/xml/internal/serializer/WriterChain
> com/sun/tools/javac/api/JavacTaskPool$ReusableContext$ReusableJavaCompiler
> com/sun/tools/javac/file/JavacFileManager$1
> com/sun/tools/javac/file/JavacFileManager$ArchiveContainer
> com/sun/tools/javac/file/JavacFileManager$Container
> com/sun/tools/javac/file/JavacFileManager$DirectoryContainer
> com/sun/tools/javac/file/JavacFileManager$JRTImageContainer
> com/sun/tools/javac/file/Locations
> com/sun/tools/javac/main/JavaCompiler
> com/sun/tools/javac/processing/JavacProcessingEnvironment$DiscoveredProcessors
> com/sun/tools/javac/processing/JavacProcessingEnvironment$ServiceIterator
> com/sun/tools/jdi/SharedMemoryConnection
> com/sun/tools/jdi/SocketConnection
> com/sun/tools/sjavac/PubApiExtractor
> com/sun/xml/internal/stream/Entity$ScannedEntity
> com/sun/xml/internal/stream/XMLEventReaderImpl
> com/sun/xml/internal/stream/writers/XMLDOMWriterImpl
> com/sun/xml/internal/stream/writers/XMLEventWriterImpl
> com/sun/xml/internal/stream/writers/XMLStreamWriterImpl
> java/awt/SplashScreen
> java/util/logging/ConsoleHandler
> java/util/logging/FileHandler
> java/util/logging/Handler
> java/util/logging/MemoryHandler
> java/util/logging/SocketHandler
> java/util/logging/StreamHandler
> javax/naming/Context
> javax/naming/InitialContext
> javax/naming/NamingEnumeration
> javax/naming/directory/BasicAttribute$ValuesEnumImpl
> javax/naming/directory/BasicAttributes$AttrEnumImpl
> javax/naming/directory/BasicAttributes$IDEnumImpl
> javax/naming/ldap/StartTlsResponse
> javax/naming/spi/ContinuationContext
> javax/smartcardio/CardChannel
> javax/sql/PooledConnection
> javax/swing/ProgressMonitor
> javax/swing/text/rtf/RTFReader$AttributeTrackingDestination
> javax/swing/text/rtf/RTFReader$ColortblDestination
> javax/swing/text/rtf/RTFReader$Destination
> javax/swing/text/rtf/RTFReader$DiscardingDestination
> javax/swing/text/rtf/RTFReader$FonttblDestination
> javax/swing/text/rtf/RTFReader$StylesheetDestination
> javax/swing/text/rtf/RTFReader$StylesheetDestination$StyleDefiningDestination
> javax/swing/text/rtf/RTFReader$TextHandlingDestination
> javax/xml/stream/XMLEventReader
> javax/xml/stream/XMLEventWriter
> javax/xml/stream/XMLStreamReader
> javax/xml/stream/XMLStreamWriter
> javax/xml/stream/util/EventReaderDelegate
> javax/xml/stream/util/StreamReaderDelegate
> jdk/internal/jrtfs/ExplodedImage
> jdk/internal/util/xml/XMLStreamWriter
> jdk/internal/util/xml/impl/XMLStreamWriterImpl
> jdk/jfr/internal/consumer/ChunkParser
> jdk/jshell/SourceCodeAnalysisImpl
> jdk/tools/jlink/internal/Archive
> jdk/tools/jlink/internal/DirArchive
> jdk/tools/jlink/internal/JarArchive
> jdk/tools/jlink/internal/JmodArchive
> org/graalvm/compiler/code/CompilationResult
> org/graalvm/compiler/code/DataSection
> org/graalvm/compiler/debug/DiagnosticsOutputDirectory
> org/w3c/dom/html/HTMLDocument
> sun/awt/image/ImageDecoder
> sun/jvm/hotspot/debugger/DataSource
> sun/jvm/hotspot/debugger/InputLexer
> sun/jvm/hotspot/debugger/MappedByteBufferDataSource
> sun/jvm/hotspot/debugger/RandomAccessFileDataSource
> sun/jvm/hotspot/debugger/posix/AddressDataSource
> sun/jvm/hotspot/debugger/posix/elf/ELFFile
> sun/jvm/hotspot/debugger/posix/elf/ELFFileParser$ELFFileImpl
> sun/jvm/hotspot/debugger/win32/coff/COFFFile
> sun/jvm/hotspot/debugger/win32/coff/COFFFileParser$COFFFileImpl
> sun/jvm/hotspot/debugger/windbg/AddressDataSource
> sun/jvm/hotspot/debugger/windbg/DLL
> sun/net/ProgressSource
> sun/net/httpserver/ExchangeImpl
> sun/net/www/URLConnection
> sun/rmi/log/ReliableLog
> sun/rmi/runtime/Log$InternalStreamHandler
> sun/rmi/transport/Connection
> sun/rmi/transport/tcp/TCPConnection
> sun/security/smartcardio/ChannelImpl
> sun/tools/java/ClassPath