Class JarFile
- All Implemented Interfaces:
Closeable
,AutoCloseable
JarFile
class is used to read the contents of a jar file
from any file that can be opened with java.io.RandomAccessFile
.
It extends the class java.util.zip.ZipFile
with support
for reading an optional Manifest
entry, and support for
processing multi-release jar files. The Manifest
can be used
to specify meta-information about the jar file and its entries.
A multi-release jar file is a jar file that
contains a manifest with a main attribute named "Multi-Release",
a set of "base" entries, some of which are public classes with public
or protected methods that comprise the public interface of the jar file,
and a set of "versioned" entries contained in subdirectories of the
"META-INF/versions" directory. The versioned entries are partitioned by the
major version of the Java platform. A versioned entry, with a version
n
, 8 < n
, in the "META-INF/versions/{n}" directory overrides
the base entry as well as any entry with a version number i
where
8 < i < n
.
By default, a JarFile
for a multi-release jar file is configured
to process the multi-release jar file as if it were a plain (unversioned) jar
file, and as such an entry name is associated with at most one base entry.
The JarFile
may be configured to process a multi-release jar file by
creating the JarFile
with the
JarFile(File, boolean, int, Runtime.Version)
constructor. The
Runtime.Version
object sets a maximum version used when searching for
versioned entries. When so configured, an entry name
can correspond with at most one base entry and zero or more versioned
entries. A search is required to associate the entry name with the latest
versioned entry whose version is less than or equal to the maximum version
(see getEntry(String)
).
Class loaders that utilize JarFile
to load classes from the
contents of JarFile
entries should construct the JarFile
by invoking the JarFile(File, boolean, int, Runtime.Version)
constructor with the value Runtime.version()
assigned to the last
argument. This assures that classes compatible with the major
version of the running JVM are loaded from multi-release jar files.
If the verify
flag is on when opening a signed jar file, the content
of the jar entry is verified against the signature embedded inside the manifest
that is associated with its path name
. For a
multi-release jar file, the content of a versioned entry is verified against
its own signature and JarEntry.getCodeSigners()
returns its own signers.
Please note that the verification process does not include validating the
signer's certificate. A caller should inspect the return value of
JarEntry.getCodeSigners()
to further determine if the signature
can be trusted.
Unless otherwise noted, passing a null
argument to a constructor
or method in this class will cause a NullPointerException
to be
thrown.
- Implementation Note:
- If the API can not be used to configure a
JarFile
(e.g. to override the configuration of a compiled application or library), twoSystem
properties are available.-
jdk.util.jar.version
can be assigned a value that is theString
representation of a non-negative integer<= Runtime.version().feature()
. The value is used to set the effective runtime version to something other than the default value obtained by evaluatingRuntime.version().feature()
. The effective runtime version is the version that theJarFile(File, boolean, int, Runtime.Version)
constructor uses when the value of the last argument isJarFile.runtimeVersion()
. -
jdk.util.jar.enableMultiRelease
can be assigned one of the threeString
values true, false, or force. The value true, the default value, enables multi-release jar file processing. The value false disables multi-release jar processing, ignoring the "Multi-Release" manifest attribute, and the versioned directories in a multi-release jar file if they exist. Furthermore, the methodisMultiRelease()
returns false. The value force causes theJarFile
to be initialized to runtime versioning after construction. It effectively does the same as this code:(new JarFile(File, boolean, int, JarFile.runtimeVersion())
.
-
- Since:
- 1.2
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionstatic final int
Central directory (CEN) header internal file attributes field offset.static final int
Central directory (CEN) header external file attributes field offset.static final int
Central directory (CEN) header comment length field offset.static final int
Central directory (CEN) header uncompressed file crc-32 value field offset.static final int
Central directory (CEN) header disk number start field offset.static final int
Central directory (CEN) header extra field length field offset.static final int
Central directory (CEN) header encrypt, decrypt flags field offset.static final int
Central directory (CEN) header size in bytes (including signature).static final int
Central directory (CEN) header compression method field offset.static final int
Central directory (CEN) header uncompressed size field offset.static final int
Central directory (CEN) header filename length field offset.static final int
Central directory (CEN) header LOC header offset field offset.static final long
Central directory (CEN) header signature.static final int
Central directory (CEN) header compressed size field offset.static final int
Central directory (CEN) header modification time field offset.static final int
Central directory (CEN) header version made by field offset.static final int
Central directory (CEN) header version needed to extract field offset.static final int
End of central directory (END) header ZIP file comment length field offset.static final int
End of central directory (END) header size in bytes (including signature).static final int
End of central directory (END) header offset for the first CEN header field offset.static final long
End of central directory (END) header signature.static final int
End of central directory (END) header central directory size in bytes field offset.static final int
End of central directory (END) header number of entries on this disk field offset.static final int
End of central directory (END) header total number of entries field offset.static final int
Extra local (EXT) header uncompressed file crc-32 value field offset.static final int
Extra local (EXT) header size in bytes (including signature).static final int
Extra local (EXT) header uncompressed size field offset.static final long
Extra local (EXT) header signature.static final int
Extra local (EXT) header compressed size field offset.static final int
Local file (LOC) header uncompressed file crc-32 value field offset.static final int
Local file (LOC) header extra field length field offset.static final int
Local file (LOC) header general purpose bit flag field offset.static final int
Local file (LOC) header size in bytes (including signature).static final int
Local file (LOC) header compression method field offset.static final int
Local file (LOC) header uncompressed size field offset.static final int
Local file (LOC) header filename length field offset.static final long
Local file (LOC) header signature.static final int
Local file (LOC) header compressed size field offset.static final int
Local file (LOC) header modification time field offset.static final int
Local file (LOC) header version needed to extract field offset.static final String
The JAR manifest file name.Fields inherited from class java.util.zip.ZipFile
OPEN_DELETE, OPEN_READ
-
Constructor Summary
ConstructorDescriptionCreates a newJarFile
to read from the specifiedFile
object.Creates a newJarFile
to read from the specifiedFile
object.Creates a newJarFile
to read from the specifiedFile
object in the specified mode.JarFile
(File file, boolean verify, int mode, Runtime.Version version) Creates a newJarFile
to read from the specifiedFile
object in the specified mode.Creates a newJarFile
to read from the specified filename
.Creates a newJarFile
to read from the specified filename
. -
Method Summary
Modifier and TypeMethodDescriptionstatic Runtime.Version
Returns the version that represents the unversioned configuration of a multi-release jar file.entries()
Returns an enumeration of the jar file entries.Returns theZipEntry
for the given base entry name ornull
if not found.Returns an input stream for reading the contents of the specified ZIP file entry.getJarEntry
(String name) Returns theJarEntry
for the given base entry name ornull
if not found.Returns the jar file manifest, ornull
if none.final Runtime.Version
Returns the maximum version used when searching for versioned entries.final boolean
Indicates whether or not this jar file is a multi-release jar file.static Runtime.Version
Returns the version that represents the effective runtime versioned configuration of a multi-release jar file.stream()
Returns an orderedStream
over the jar file entries.Returns aStream
of the versioned jar file entries.
-
Field Details
-
MANIFEST_NAME
-
LOCSIG
static final long LOCSIGLocal file (LOC) header signature.- See Also:
-
EXTSIG
static final long EXTSIGExtra local (EXT) header signature.- See Also:
-
CENSIG
static final long CENSIGCentral directory (CEN) header signature.- See Also:
-
ENDSIG
static final long ENDSIGEnd of central directory (END) header signature.- See Also:
-
LOCHDR
static final int LOCHDRLocal file (LOC) header size in bytes (including signature).- See Also:
-
EXTHDR
static final int EXTHDRExtra local (EXT) header size in bytes (including signature).- See Also:
-
CENHDR
static final int CENHDRCentral directory (CEN) header size in bytes (including signature).- See Also:
-
ENDHDR
static final int ENDHDREnd of central directory (END) header size in bytes (including signature).- See Also:
-
LOCVER
static final int LOCVERLocal file (LOC) header version needed to extract field offset.- See Also:
-
LOCFLG
static final int LOCFLGLocal file (LOC) header general purpose bit flag field offset.- See Also:
-
LOCHOW
static final int LOCHOWLocal file (LOC) header compression method field offset.- See Also:
-
LOCTIM
static final int LOCTIMLocal file (LOC) header modification time field offset.- See Also:
-
LOCCRC
static final int LOCCRCLocal file (LOC) header uncompressed file crc-32 value field offset.- See Also:
-
LOCSIZ
static final int LOCSIZLocal file (LOC) header compressed size field offset.- See Also:
-
LOCLEN
static final int LOCLENLocal file (LOC) header uncompressed size field offset.- See Also:
-
LOCNAM
static final int LOCNAMLocal file (LOC) header filename length field offset.- See Also:
-
LOCEXT
static final int LOCEXTLocal file (LOC) header extra field length field offset.- See Also:
-
EXTCRC
static final int EXTCRCExtra local (EXT) header uncompressed file crc-32 value field offset.- See Also:
-
EXTSIZ
static final int EXTSIZExtra local (EXT) header compressed size field offset.- See Also:
-
EXTLEN
static final int EXTLENExtra local (EXT) header uncompressed size field offset.- See Also:
-
CENVEM
static final int CENVEMCentral directory (CEN) header version made by field offset.- See Also:
-
CENVER
static final int CENVERCentral directory (CEN) header version needed to extract field offset.- See Also:
-
CENFLG
static final int CENFLGCentral directory (CEN) header encrypt, decrypt flags field offset.- See Also:
-
CENHOW
static final int CENHOWCentral directory (CEN) header compression method field offset.- See Also:
-
CENTIM
static final int CENTIMCentral directory (CEN) header modification time field offset.- See Also:
-
CENCRC
static final int CENCRCCentral directory (CEN) header uncompressed file crc-32 value field offset.- See Also:
-
CENSIZ
static final int CENSIZCentral directory (CEN) header compressed size field offset.- See Also:
-
CENLEN
static final int CENLENCentral directory (CEN) header uncompressed size field offset.- See Also:
-
CENNAM
static final int CENNAMCentral directory (CEN) header filename length field offset.- See Also:
-
CENEXT
static final int CENEXTCentral directory (CEN) header extra field length field offset.- See Also:
-
CENCOM
static final int CENCOMCentral directory (CEN) header comment length field offset.- See Also:
-
CENDSK
static final int CENDSKCentral directory (CEN) header disk number start field offset.- See Also:
-
CENATT
static final int CENATTCentral directory (CEN) header internal file attributes field offset.- See Also:
-
CENATX
static final int CENATXCentral directory (CEN) header external file attributes field offset.- See Also:
-
CENOFF
static final int CENOFFCentral directory (CEN) header LOC header offset field offset.- See Also:
-
ENDSUB
static final int ENDSUBEnd of central directory (END) header number of entries on this disk field offset.- See Also:
-
ENDTOT
static final int ENDTOTEnd of central directory (END) header total number of entries field offset.- See Also:
-
ENDSIZ
static final int ENDSIZEnd of central directory (END) header central directory size in bytes field offset.- See Also:
-
ENDOFF
static final int ENDOFFEnd of central directory (END) header offset for the first CEN header field offset.- See Also:
-
ENDCOM
static final int ENDCOMEnd of central directory (END) header ZIP file comment length field offset.- See Also:
-
-
Constructor Details
-
JarFile
Creates a newJarFile
to read from the specified filename
. TheJarFile
will be verified if it is signed.- Parameters:
name
- the name of the jar file to be opened for reading- Throws:
IOException
- if an I/O error has occurred
-
JarFile
Creates a newJarFile
to read from the specified filename
.- Parameters:
name
- the name of the jar file to be opened for readingverify
- whether or not to verify the jar file if it is signed.- Throws:
IOException
- if an I/O error has occurred
-
JarFile
Creates a newJarFile
to read from the specifiedFile
object. TheJarFile
will be verified if it is signed.- Parameters:
file
- the jar file to be opened for reading- Throws:
IOException
- if an I/O error has occurred
-
JarFile
Creates a newJarFile
to read from the specifiedFile
object.- Parameters:
file
- the jar file to be opened for readingverify
- whether or not to verify the jar file if it is signed.- Throws:
IOException
- if an I/O error has occurred
-
JarFile
Creates a newJarFile
to read from the specifiedFile
object in the specified mode. The mode argument must be eitherOPEN_READ
orOPEN_READ | OPEN_DELETE
.- Parameters:
file
- the jar file to be opened for readingverify
- whether or not to verify the jar file if it is signed.mode
- the mode in which the file is to be opened- Throws:
IOException
- if an I/O error has occurredIllegalArgumentException
- if themode
argument is invalid- Since:
- 1.3
-
JarFile
Creates a newJarFile
to read from the specifiedFile
object in the specified mode. The mode argument must be eitherOPEN_READ
orOPEN_READ | OPEN_DELETE
. The version argument, after being converted to a canonical form, is used to configure theJarFile
for processing multi-release jar files.The canonical form derived from the version parameter is
Runtime.Version.parse(Integer.toString(n))
wheren
isMath.max(version.feature(), JarFile.baseVersion().feature())
.- Parameters:
file
- the jar file to be opened for readingverify
- whether or not to verify the jar file if it is signed.mode
- the mode in which the file is to be openedversion
- specifies the release version for a multi-release jar file- Throws:
IOException
- if an I/O error has occurredIllegalArgumentException
- if themode
argument is invalidNullPointerException
- ifversion
isnull
- Since:
- 9
-
-
Method Details
-
baseVersion
Returns the version that represents the unversioned configuration of a multi-release jar file.- Returns:
- the version that represents the unversioned configuration
- Since:
- 9
-
runtimeVersion
Returns the version that represents the effective runtime versioned configuration of a multi-release jar file.By default the feature version number of the returned
Version
will be equal to the feature version number ofRuntime.version()
. However, if thejdk.util.jar.version
property is set, the returnedVersion
is derived from that property and feature version numbers may not be equal.- Returns:
- the version that represents the runtime versioned configuration
- Since:
- 9
-
getVersion
Returns the maximum version used when searching for versioned entries.If this
JarFile
is not a multi-release jar file or is not configured to be processed as such, then the version returned will be the same as that returned frombaseVersion()
.- Returns:
- the maximum version
- Since:
- 9
-
isMultiRelease
public final boolean isMultiRelease()Indicates whether or not this jar file is a multi-release jar file.- Returns:
- true if this JarFile is a multi-release jar file
- Since:
- 9
-
getManifest
Returns the jar file manifest, ornull
if none.- Returns:
- the jar file manifest, or
null
if none - Throws:
IllegalStateException
- may be thrown if the jar file has been closedIOException
- if an I/O error has occurred
-
getJarEntry
Returns theJarEntry
for the given base entry name ornull
if not found.If this
JarFile
is a multi-release jar file and is configured to be processed as such, then a search is performed to find and return aJarEntry
that is the latest versioned entry associated with the given entry name. The returnedJarEntry
is the versioned entry corresponding to the given base entry name prefixed with the string"META-INF/versions/{n}/"
, for the largest value ofn
for which an entry exists. If such a versioned entry does not exist, then theJarEntry
for the base entry is returned, otherwisenull
is returned if no entries are found. The initial value for the versionn
is the maximum version as returned by the methodgetVersion()
.- Implementation Requirements:
- This implementation invokes
getEntry(String)
. - Parameters:
name
- the jar file entry name- Returns:
- the
JarEntry
for the given entry name, or the versioned entry name, ornull
if not found - Throws:
IllegalStateException
- may be thrown if the jar file has been closed- See Also:
-
getEntry
Returns theZipEntry
for the given base entry name ornull
if not found.If this
JarFile
is a multi-release jar file and is configured to be processed as such, then a search is performed to find and return aZipEntry
that is the latest versioned entry associated with the given entry name. The returnedZipEntry
is the versioned entry corresponding to the given base entry name prefixed with the string"META-INF/versions/{n}/"
, for the largest value ofn
for which an entry exists. If such a versioned entry does not exist, then theZipEntry
for the base entry is returned, otherwisenull
is returned if no entries are found. The initial value for the versionn
is the maximum version as returned by the methodgetVersion()
.- Overrides:
getEntry
in classZipFile
- Implementation Requirements:
- This implementation may return a versioned entry for the requested name even if there is not a corresponding base entry. This can occur if there is a private or package-private versioned entry that matches. If a subclass overrides this method, assure that the override method invokes
super.getEntry(name)
to obtain all versioned entries. - Parameters:
name
- the jar file entry name- Returns:
- the
ZipEntry
for the given entry name or the versioned entry name ornull
if not found - Throws:
IllegalStateException
- may be thrown if the jar file has been closed- See Also:
-
entries
Returns an enumeration of the jar file entries.- Overrides:
entries
in classZipFile
- Returns:
- an enumeration of the jar file entries
- Throws:
IllegalStateException
- may be thrown if the jar file has been closed
-
stream
Returns an orderedStream
over the jar file entries. Entries appear in theStream
in the order they appear in the central directory of the jar file.- Overrides:
stream
in classZipFile
- Returns:
- an ordered
Stream
of entries in this jar file - Throws:
IllegalStateException
- if the jar file has been closed- Since:
- 1.8
-
versionedStream
Returns aStream
of the versioned jar file entries.If this
JarFile
is a multi-release jar file and is configured to be processed as such, then an entry in the stream is the latest versioned entry associated with the corresponding base entry name. The maximum version of the latest versioned entry is the version returned bygetVersion()
. The returned stream may include an entry that only exists as a versioned entry. If the jar file is not a multi-release jar file or theJarFile
is not configured for processing a multi-release jar file, this method returns the same stream thatstream()
returns.- Returns:
- stream of versioned entries
- Since:
- 10
-
getInputStream
Returns an input stream for reading the contents of the specified ZIP file entry.- Overrides:
getInputStream
in classZipFile
- API Note:
- The
InputStream
returned by this method can wrap anInflaterInputStream
, whoseread(byte[], int, int)
method can modify any element of the output buffer. - Parameters:
ze
- the ZIP file entry- Returns:
- an input stream for reading the contents of the specified ZIP file entry or null if the ZIP file entry does not exist within the jar file
- Throws:
ZipException
- if a ZIP file format error has occurredIOException
- if an I/O error has occurredSecurityException
- if any of the jar file entries are incorrectly signed.IllegalStateException
- may be thrown if the jar file has been closed
-