Summary: Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

public class

URLClassLoader

extends SecureClassLoader

java.lang.Object
↳	java.lang.ClassLoader
	↳	java.security.SecureClassLoader
		↳	java.net.URLClassLoader

Known Direct Subclasses

AppletClassLoader, MLet

Known Indirect Subclasses

PrivateMLet

Class Overview

This class loader is used to load classes and resources from a search path of URLs referring to both JAR files and directories. Any URL that ends with a '/' is assumed to refer to a directory. Otherwise, the URL is assumed to refer to a JAR file which will be opened as needed.

The AccessControlContext of the thread that created the instance of URLClassLoader will be used when subsequently loading classes and resources.

The classes that are loaded are by default granted permission only to access the URLs specified when the URLClassLoader was created.

Summary

Public Constructors
	URLClassLoader(URL[] urls, ClassLoader parent) Constructs a new URLClassLoader for the given URLs.
	URLClassLoader(URL[] urls) Constructs a new URLClassLoader for the specified URLs using the default delegation parent `ClassLoader`.
	URLClassLoader(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory) Constructs a new URLClassLoader for the specified URLs, parent class loader, and URLStreamHandlerFactory.

Public Methods
URL	findResource(String name) Finds the resource with the specified name on the URL search path.
Enumeration<URL>	findResources(String name) Returns an Enumeration of URLs representing all of the resources on the URL search path having the specified name.
URL[]	getURLs() Returns the search path of URLs for loading classes and resources.
static URLClassLoader	newInstance(URL[] urls, ClassLoader parent) Creates a new instance of URLClassLoader for the specified URLs and parent class loader.
static URLClassLoader	newInstance(URL[] urls) Creates a new instance of URLClassLoader for the specified URLs and default parent class loader.

Protected Methods
void	addURL(URL url) Appends the specified URL to the list of URLs to search for classes and resources.
Package	definePackage(String name, Manifest man, URL url) Defines a new package by name in this ClassLoader.
Class<?>	findClass(String name) Finds and loads the class with the specified name from the URL search path.
PermissionCollection	getPermissions(CodeSource codesource) Returns the permissions for the given codesource object.

[Expand]

Inherited Methods

From class java.security.SecureClassLoader

From class java.lang.ClassLoader

synchronized void	clearAssertionStatus() Sets the default assertion status for this class loader to `false` and discards any package defaults or class assertion status settings associated with the class loader.
final Class<?>	defineClass(String name, ByteBuffer b, ProtectionDomain protectionDomain) Converts a java.nio.ByteBuffer `ByteBuffer` into an instance of class `Class`, with an optional `ProtectionDomain`.
final Class<?>	defineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) Converts an array of bytes into an instance of class `Class`, with an optional `ProtectionDomain`.
final Class<?>	defineClass(String name, byte[] b, int off, int len) Converts an array of bytes into an instance of class `Class`.
final Class<?>	defineClass(byte[] b, int off, int len) This method is deprecated. Replaced by `defineClass(String, byte[], int, int)`
Package	definePackage(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase) Defines a package by name in this `ClassLoader`.
Class<?>	findClass(String name) Finds the class with the specified binary name.
String	findLibrary(String libname) Returns the absolute path name of a native library.
final Class<?>	findLoadedClass(String name) Returns the class with the given binary name if this loader has been recorded by the Java virtual machine as an initiating loader of a class with that binary name.
URL	findResource(String name) Finds the resource with the given name.
Enumeration<URL>	findResources(String name) Returns an enumeration of `URL` objects representing all the resources with the given name.
final Class<?>	findSystemClass(String name) Finds a class with the specified binary name, loading it if necessary.
Package	getPackage(String name) Returns a `Package` that has been defined by this class loader or any of its ancestors.
Package[]	getPackages() Returns all of the `Packages` defined by this class loader and its ancestors.
final ClassLoader	getParent() Returns the parent class loader for delegation.
URL	getResource(String name) Finds the resource with the given name.
InputStream	getResourceAsStream(String name) Returns an input stream for reading the specified resource.
Enumeration<URL>	getResources(String name) Finds all the resources with the given name.
static ClassLoader	getSystemClassLoader() Returns the system class loader for delegation.
static URL	getSystemResource(String name) Find a resource of the specified name from the search path used to load classes.
static InputStream	getSystemResourceAsStream(String name) Open for reading, a resource of the specified name from the search path used to load classes.
static Enumeration<URL>	getSystemResources(String name) Finds all resources of the specified name from the search path used to load classes.
synchronized Class<?>	loadClass(String name, boolean resolve) Loads the class with the specified binary name.
Class<?>	loadClass(String name) Loads the class with the specified binary name.
final void	resolveClass(Class<?> c) Links the specified class.
synchronized void	setClassAssertionStatus(String className, boolean enabled) Sets the desired assertion status for the named top-level class in this class loader and any nested classes contained therein.
synchronized void	setDefaultAssertionStatus(boolean enabled) Sets the default assertion status for this class loader.
synchronized void	setPackageAssertionStatus(String packageName, boolean enabled) Sets the package default assertion status for the named package.
final void	setSigners(Class<?> c, Object[] signers) Sets the signers of a class.

From class java.lang.Object

Object	clone() Creates and returns a copy of this object.
boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
final Class<?>	getClass() Returns the runtime class of this `Object`.
int	hashCode() Returns a hash code value for the object.
final void	notify() Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll() Wakes up all threads that are waiting on this object's monitor.
String	toString() Returns a string representation of the object.
final void	wait() Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.
final void	wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
final void	wait(long timeout) Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.

Public Constructors

public URLClassLoader (URL[] urls, ClassLoader parent)

Constructs a new URLClassLoader for the given URLs. The URLs will be searched in the order specified for classes and resources after first searching in the specified parent class loader. Any URL that ends with a '/' is assumed to refer to a directory. Otherwise, the URL is assumed to refer to a JAR file which will be downloaded and opened as needed.

If there is a security manager, this method first calls the security manager's checkCreateClassLoader method to ensure creation of a class loader is allowed.

Parameters

urls	the URLs from which to load classes and resources
parent	the parent class loader for delegation

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader` method doesn't allow creation of a class loader.

public URLClassLoader (URL[] urls)

Constructs a new URLClassLoader for the specified URLs using the default delegation parent ClassLoader. The URLs will be searched in the order specified for classes and resources after first searching in the parent class loader. Any URL that ends with a '/' is assumed to refer to a directory. Otherwise, the URL is assumed to refer to a JAR file which will be downloaded and opened as needed.

If there is a security manager, this method first calls the security manager's checkCreateClassLoader method to ensure creation of a class loader is allowed.

Parameters

urls	the URLs from which to load classes and resources

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader` method doesn't allow creation of a class loader.

public URLClassLoader (URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)

Constructs a new URLClassLoader for the specified URLs, parent class loader, and URLStreamHandlerFactory. The parent argument will be used as the parent class loader for delegation. The factory argument will be used as the stream handler factory to obtain protocol handlers when creating new jar URLs.

If there is a security manager, this method first calls the security manager's checkCreateClassLoader method to ensure creation of a class loader is allowed.

Parameters

urls	the URLs from which to load classes and resources
parent	the parent class loader for delegation
factory	the URLStreamHandlerFactory to use when creating URLs

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader` method doesn't allow creation of a class loader.

Public Methods

public URL findResource (String name)

Finds the resource with the specified name on the URL search path.

Parameters

name	the name of the resource

Returns

a URL for the resource, or null if the resource could not be found.

public Enumeration<URL> findResources (String name)

Returns an Enumeration of URLs representing all of the resources on the URL search path having the specified name.

Parameters

name	the resource name

Returns

an Enumeration of URLs

Throws

IOException	if an I/O exception occurs

public URL[] getURLs ()

Returns the search path of URLs for loading classes and resources. This includes the original list of URLs specified to the constructor, along with any URLs subsequently appended by the addURL() method.

Returns

the search path of URLs for loading classes and resources.

public static URLClassLoader newInstance (URL[] urls, ClassLoader parent)

Creates a new instance of URLClassLoader for the specified URLs and parent class loader. If a security manager is installed, the loadClass method of the URLClassLoader returned by this method will invoke the SecurityManager.checkPackageAccess method before loading the class.

Parameters

urls	the URLs to search for classes and resources
parent	the parent class loader for delegation

Returns

the resulting class loader

public static URLClassLoader newInstance (URL[] urls)

Creates a new instance of URLClassLoader for the specified URLs and default parent class loader. If a security manager is installed, the loadClass method of the URLClassLoader returned by this method will invoke the SecurityManager.checkPackageAccess before loading the class.

Parameters

urls	the URLs to search for classes and resources

Returns

the resulting class loader

Protected Methods

protected void addURL (URL url)

Appends the specified URL to the list of URLs to search for classes and resources.

Parameters

url	the URL to be added to the search path of URLs

protected Package definePackage (String name, Manifest man, URL url)

Defines a new package by name in this ClassLoader. The attributes contained in the specified Manifest will be used to obtain package version and sealing information. For sealed packages, the additional URL specifies the code source URL from which the package was loaded.

Parameters

name	the package name
man	the Manifest containing package version and sealing information
url	the code source url for the package, or null if none

Returns

the newly defined Package object

Throws

IllegalArgumentException	if the package name duplicates an existing package either in this class loader or one of its ancestors

protected Class<?> findClass (String name)

Finds and loads the class with the specified name from the URL search path. Any URLs referring to JAR files are loaded and opened as needed until the class is found.

Parameters

name	the name of the class

Returns

the resulting class

Throws

ClassNotFoundException	if the class could not be found

protected PermissionCollection getPermissions (CodeSource codesource)

Returns the permissions for the given codesource object. The implementation of this method first calls super.getPermissions and then adds permissions based on the URL of the codesource.

If the protocol of this URL is "jar", then the permission granted is based on the permission that is required by the URL of the Jar file.

If the protocol is "file" and the path specifies a file, then permission to read that file is granted. If protocol is "file" and the path is a directory, permission is granted to read all files and (recursively) all files and subdirectories contained in that directory.

If the protocol is not "file", then permission to connect to and accept connections from the URL's host is granted.

Parameters

codesource	the codesource

Returns

the permissions granted to the codesource

Interfaces

Classes

Enums

Exceptions

URLClassLoader

Class Overview

Summary

Public Constructors

public URLClassLoader (URL[] urls, ClassLoader parent)

Parameters

Throws

See Also

public URLClassLoader (URL[] urls)

Parameters

Throws

See Also

public URLClassLoader (URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)

Parameters

Throws

See Also

Public Methods

public URL findResource (String name)

Parameters

Returns

public Enumeration<URL> findResources (String name)

Parameters

Returns

Throws

public URL[] getURLs ()

Returns

public static URLClassLoader newInstance (URL[] urls, ClassLoader parent)

Parameters

Returns

public static URLClassLoader newInstance (URL[] urls)

Parameters

Returns

Protected Methods

protected void addURL (URL url)

Parameters

protected Package definePackage (String name, Manifest man, URL url)

Parameters

Returns

Throws

protected Class<?> findClass (String name)

Parameters

Returns

Throws

protected PermissionCollection getPermissions (CodeSource codesource)

Parameters

Returns