Class JarFile
- java.lang.Object
-
- java.util.zip.ZipFile
-
- java.util.jar.JarFile
- All Implemented Interfaces:
-
Closeable
,AutoCloseable
public class JarFile extends ZipFile
The 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 verfieid 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:
-
Manifest
,ZipFile
,JarEntry
Field Summary
Modifier and Type | Field | Description |
---|---|---|
static int | CENATT | |
static int | CENATX | |
static int | CENCOM | |
static int | CENCRC | |
static int | CENDSK | |
static int | CENEXT | |
static int | CENFLG | |
static int | CENHDR | |
static int | CENHOW | |
static int | CENLEN | |
static int | CENNAM | |
static int | CENOFF | |
static long | CENSIG | |
static int | CENSIZ | |
static int | CENTIM | |
static int | CENVEM | |
static int | CENVER | |
static int | ENDCOM | |
static int | ENDHDR | |
static int | ENDOFF | |
static long | ENDSIG | |
static int | ENDSIZ | |
static int | ENDSUB | |
static int | ENDTOT | |
static int | EXTCRC | |
static int | EXTHDR | |
static int | EXTLEN | |
static long | EXTSIG | |
static int | EXTSIZ | |
static int | LOCCRC | |
static int | LOCEXT | |
static int | LOCFLG | |
static int | LOCHDR | |
static int | LOCHOW | |
static int | LOCLEN | |
static int | LOCNAM | |
static long | LOCSIG | |
static int | LOCSIZ | |
static int | LOCTIM | |
static int | LOCVER | |
static String | MANIFEST_NAME | The JAR manifest file name. |
Fields declared in class java.util.zip.ZipFile
OPEN_DELETE, OPEN_READ
Constructor Summary
Constructor | Description |
---|---|
JarFile(File file) | Creates a new |
JarFile(File file,
boolean verify) | Creates a new |
JarFile(File file,
boolean verify,
int mode) | Creates a new |
JarFile(File file,
boolean verify,
int mode,
Runtime.Version version) | Creates a new |
JarFile(String name) | Creates a new |
JarFile(String name,
boolean verify) | Creates a new |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
static Runtime.Version | baseVersion() | Returns the version that represents the unversioned configuration of a multi-release jar file. |
Enumeration<JarEntry> | entries() | Returns an enumeration of the jar file entries. |
ZipEntry | getEntry(String name) | Returns the |
InputStream | getInputStream(ZipEntry ze) | Returns an input stream for reading the contents of the specified zip file entry. |
JarEntry | getJarEntry(String name) | Returns the |
Manifest | getManifest() | Returns the jar file manifest, or |
Runtime.Version | getVersion() | Returns the maximum version used when searching for versioned entries. |
boolean | isMultiRelease() | Indicates whether or not this jar file is a multi-release jar file. |
static Runtime.Version | runtimeVersion() | Returns the version that represents the effective runtime versioned configuration of a multi-release jar file. |
Stream<JarEntry> | stream() | Returns an ordered |
Stream<JarEntry> | versionedStream() | Returns a |
Methods declared in class java.util.zip.ZipFile
close, finalize, getComment, getName, size
Methods declared in class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Field Detail
MANIFEST_NAME
public static final String MANIFEST_NAME
The JAR manifest file name.
- See Also:
- Constant Field Values
LOCSIG
public static final long LOCSIG
- See Also:
- Constant Field Values
EXTSIG
public static final long EXTSIG
- See Also:
- Constant Field Values
CENSIG
public static final long CENSIG
- See Also:
- Constant Field Values
ENDSIG
public static final long ENDSIG
- See Also:
- Constant Field Values
LOCHDR
public static final int LOCHDR
- See Also:
- Constant Field Values
EXTHDR
public static final int EXTHDR
- See Also:
- Constant Field Values
CENHDR
public static final int CENHDR
- See Also:
- Constant Field Values
ENDHDR
public static final int ENDHDR
- See Also:
- Constant Field Values
LOCVER
public static final int LOCVER
- See Also:
- Constant Field Values
LOCFLG
public static final int LOCFLG
- See Also:
- Constant Field Values
LOCHOW
public static final int LOCHOW
- See Also:
- Constant Field Values
LOCTIM
public static final int LOCTIM
- See Also:
- Constant Field Values
LOCCRC
public static final int LOCCRC
- See Also:
- Constant Field Values
LOCSIZ
public static final int LOCSIZ
- See Also:
- Constant Field Values
LOCLEN
public static final int LOCLEN
- See Also:
- Constant Field Values
LOCNAM
public static final int LOCNAM
- See Also:
- Constant Field Values
LOCEXT
public static final int LOCEXT
- See Also:
- Constant Field Values
EXTCRC
public static final int EXTCRC
- See Also:
- Constant Field Values
EXTSIZ
public static final int EXTSIZ
- See Also:
- Constant Field Values
EXTLEN
public static final int EXTLEN
- See Also:
- Constant Field Values
CENVEM
public static final int CENVEM
- See Also:
- Constant Field Values
CENVER
public static final int CENVER
- See Also:
- Constant Field Values
CENFLG
public static final int CENFLG
- See Also:
- Constant Field Values
CENHOW
public static final int CENHOW
- See Also:
- Constant Field Values
CENTIM
public static final int CENTIM
- See Also:
- Constant Field Values
CENCRC
public static final int CENCRC
- See Also:
- Constant Field Values
CENSIZ
public static final int CENSIZ
- See Also:
- Constant Field Values
CENLEN
public static final int CENLEN
- See Also:
- Constant Field Values
CENNAM
public static final int CENNAM
- See Also:
- Constant Field Values
CENEXT
public static final int CENEXT
- See Also:
- Constant Field Values
CENCOM
public static final int CENCOM
- See Also:
- Constant Field Values
CENDSK
public static final int CENDSK
- See Also:
- Constant Field Values
CENATT
public static final int CENATT
- See Also:
- Constant Field Values
CENATX
public static final int CENATX
- See Also:
- Constant Field Values
CENOFF
public static final int CENOFF
- See Also:
- Constant Field Values
ENDSUB
public static final int ENDSUB
- See Also:
- Constant Field Values
ENDTOT
public static final int ENDTOT
- See Also:
- Constant Field Values
ENDSIZ
public static final int ENDSIZ
- See Also:
- Constant Field Values
ENDOFF
public static final int ENDOFF
- See Also:
- Constant Field Values
ENDCOM
public static final int ENDCOM
- See Also:
- Constant Field Values
Constructor Detail
JarFile
public JarFile(String name) throws IOException
Creates a new JarFile
to read from the specified file name
. The JarFile
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 -
SecurityException
- if access to the file is denied by the SecurityManager
JarFile
public JarFile(String name, boolean verify) throws IOException
Creates a new JarFile
to read from the specified file name
.
- Parameters:
-
name
- the name of the jar file to be opened for reading -
verify
- whether or not to verify the jar file if it is signed. - Throws:
-
IOException
- if an I/O error has occurred -
SecurityException
- if access to the file is denied by the SecurityManager
JarFile
public JarFile(File file) throws IOException
Creates a new JarFile
to read from the specified File
object. The JarFile
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 -
SecurityException
- if access to the file is denied by the SecurityManager
JarFile
public JarFile(File file, boolean verify) throws IOException
Creates a new JarFile
to read from the specified File
object.
- Parameters:
-
file
- the jar file to be opened for reading -
verify
- whether or not to verify the jar file if it is signed. - Throws:
-
IOException
- if an I/O error has occurred -
SecurityException
- if access to the file is denied by the SecurityManager.
JarFile
public JarFile(File file, boolean verify, int mode) throws IOException
Creates a new JarFile
to read from the specified File
object in the specified mode. The mode argument must be either OPEN_READ
or OPEN_READ | OPEN_DELETE
.
- Parameters:
-
file
- the jar file to be opened for reading -
verify
- 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 occurred -
IllegalArgumentException
- if themode
argument is invalid -
SecurityException
- if access to the file is denied by the SecurityManager - Since:
- 1.3
JarFile
public JarFile(File file, boolean verify, int mode, Runtime.Version version) throws IOException
Creates a new JarFile
to read from the specified File
object in the specified mode. The mode argument must be either OPEN_READ
or OPEN_READ | OPEN_DELETE
. The version argument, after being converted to a canonical form, is used to configure the JarFile
for processing multi-release jar files.
The canonical form derived from the version parameter is Runtime.Version.parse(Integer.toString(n))
where n
is Math.max(version.feature(), JarFile.baseVersion().feature())
.
- Parameters:
-
file
- the jar file to be opened for reading -
verify
- whether or not to verify the jar file if it is signed. -
mode
- the mode in which the file is to be opened -
version
- specifies the release version for a multi-release jar file - Throws:
-
IOException
- if an I/O error has occurred -
IllegalArgumentException
- if themode
argument is invalid -
SecurityException
- if access to the file is denied by the SecurityManager -
NullPointerException
- ifversion
isnull
- Since:
- 9
Method Detail
baseVersion
public static Runtime.Version 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
public static Runtime.Version 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 of Runtime.version()
. However, if the jdk.util.jar.version
property is set, the returned Version
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
public final Runtime.Version 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 from baseVersion()
.
- 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
public Manifest getManifest() throws IOException
Returns the jar file manifest, or null
if none.
- Returns:
- the jar file manifest, or
null
if none - Throws:
-
IllegalStateException
- may be thrown if the jar file has been closed -
IOException
- if an I/O error has occurred
getJarEntry
public JarEntry getJarEntry(String name)
Returns the JarEntry
for the given base entry name or null
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 a JarEntry
that is the latest versioned entry associated with the given entry name. The returned JarEntry
is the versioned entry corresponding to the given base entry name prefixed with the string "META-INF/versions/{n}/"
, for the largest value of n
for which an entry exists. If such a versioned entry does not exist, then the JarEntry
for the base entry is returned, otherwise null
is returned if no entries are found. The initial value for the version n
is the maximum version as returned by the method getVersion()
.
- 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:
JarEntry
getEntry
public ZipEntry getEntry(String name)
Returns the ZipEntry
for the given base entry name or null
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 a ZipEntry
that is the latest versioned entry associated with the given entry name. The returned ZipEntry
is the versioned entry corresponding to the given base entry name prefixed with the string "META-INF/versions/{n}/"
, for the largest value of n
for which an entry exists. If such a versioned entry does not exist, then the ZipEntry
for the base entry is returned, otherwise null
is returned if no entries are found. The initial value for the version n
is the maximum version as returned by the method getVersion()
.
- 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:
ZipEntry
entries
public Enumeration<JarEntry> 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
public Stream<JarEntry> stream()
Returns an ordered Stream
over the jar file entries. Entries appear in the Stream
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
public Stream<JarEntry> versionedStream()
Returns a Stream
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 by getVersion()
. 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 the JarFile
is not configured for processing a multi-release jar file, this method returns the same stream that stream()
returns.
- Returns:
- stream of versioned entries
- Since:
- 10
getInputStream
public InputStream getInputStream(ZipEntry ze) throws IOException
Returns an input stream for reading the contents of the specified zip file entry.
- Overrides:
-
getInputStream
in classZipFile
- Parameters:
-
ze
- the zip file entry - Returns:
- an input stream for reading the contents of the specified zip file entry
- Throws:
-
ZipException
- if a zip file format error has occurred -
IOException
- if an I/O error has occurred -
SecurityException
- if any of the jar file entries are incorrectly signed. -
IllegalStateException
- may be thrown if the jar file has been closed