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

Since: API Level 1

public class

URLClassLoader

extends SecureClassLoader

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

Class Overview

This class loader is responsible for loading classes and resources from a list of URLs which can refer to either directories or JAR files. Classes loaded by this URLClassLoader are granted permission to access the URLs contained in the URL search list.

Summary

Public Constructors
	URLClassLoader(URL[] urls) Constructs a new `URLClassLoader` instance.
	URLClassLoader(URL[] urls, ClassLoader parent) Constructs a new URLClassLoader instance.
	URLClassLoader(URL[] searchUrls, ClassLoader parent, URLStreamHandlerFactory factory) Constructs a new `URLClassLoader` instance.

Public Methods
URL	findResource(String name) Returns an URL referencing the specified resource or `null` if the resource could not be found.
Enumeration<URL>	findResources(String name) Returns all known URLs which point to the specified resource.
URL[]	getURLs() Returns the search list of this `URLClassLoader`.
static URLClassLoader	newInstance(URL[] urls, ClassLoader parentCl) Returns a new `URLClassLoader` instance for the given URLs and the specified `ClassLoader` as its parent.
static URLClassLoader	newInstance(URL[] urls) Returns a new `URLClassLoader` instance for the given URLs and the system `ClassLoader` as its parent.

Protected Methods
void	addURL(URL url) Adds the specified URL to the search list.
Package	definePackage(String packageName, Manifest manifest, URL url) Defines a new package using the information extracted from the specified manifest.
Class<?>	findClass(String clsName) Tries to locate and load the specified class using the known URLs.
PermissionCollection	getPermissions(CodeSource codesource) Gets all permissions for the specified `codesource`.

[Expand]

Inherited Methods

From class java.security.SecureClassLoader

From class java.lang.ClassLoader

void	clearAssertionStatus() Sets the default assertion status for this class loader to `false` and removes any package default and class assertion status settings.
final Class<?>	defineClass(String name, ByteBuffer b, ProtectionDomain protectionDomain) Defines a new class with the specified name, byte code from the byte buffer and the optional protection domain.
final Class<?>	defineClass(String className, byte[] classRep, int offset, int length, ProtectionDomain protectionDomain) Constructs a new class from an array of bytes containing a class definition in class file format and assigns the specified protection domain to the new class.
final Class<?>	defineClass(String className, byte[] classRep, int offset, int length) Constructs a new class from an array of bytes containing a class definition in class file format.
final Class<?>	defineClass(byte[] classRep, int offset, int length) This method is deprecated. Use `defineClass(String, byte[], int, int)`
Package	definePackage(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase) Defines and returns a new `Package` using the specified information.
Class<?>	findClass(String className) Overridden by subclasses, throws a `ClassNotFoundException` by default.
String	findLibrary(String libName) Returns the absolute path of the native library with the specified name, or `null`.
final Class<?>	findLoadedClass(String className) Returns the class with the specified name if it has already been loaded by the virtual machine or `null` if it has not yet been loaded.
URL	findResource(String resName) Finds the URL of the resource with the specified name.
Enumeration<URL>	findResources(String resName) Finds an enumeration of URLs for the resource with the specified name.
final Class<?>	findSystemClass(String className) Finds the class with the specified name, loading it using the system class loader if necessary.
Package	getPackage(String name) Returns the package with the specified name.
Package[]	getPackages() Returns all the packages known to this class loader.
final ClassLoader	getParent() Returns this class loader's parent.
URL	getResource(String resName) Returns the URL of the resource with the specified name.
InputStream	getResourceAsStream(String resName) Returns a stream for the resource with the specified name.
Enumeration<URL>	getResources(String resName) Returns an enumeration of URLs for the resource with the specified name.
static ClassLoader	getSystemClassLoader() Returns the system class loader.
static URL	getSystemResource(String resName) Finds the URL of the resource with the specified name.
static InputStream	getSystemResourceAsStream(String resName) Returns a stream for the resource with the specified name.
static Enumeration<URL>	getSystemResources(String resName) Returns an enumeration of URLs for the resource with the specified name.
Class<?>	loadClass(String className, boolean resolve) Loads the class with the specified name, optionally linking it after loading.
Class<?>	loadClass(String className) Loads the class with the specified name.
final void	resolveClass(Class<?> clazz) Forces a class to be linked (initialized).
void	setClassAssertionStatus(String cname, boolean enable) Sets the assertion status of the class with the specified name.
void	setDefaultAssertionStatus(boolean enable) Sets the default assertion status for this class loader.
void	setPackageAssertionStatus(String pname, boolean enable) Sets the assertion status of the package with the specified name.
final void	setSigners(Class<?> c, Object[] signers) Sets the signers of the specified class.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Called before the object's memory is reclaimed by the VM.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

Public Constructors

public URLClassLoader (URL[] urls)

Since: API Level 1

Constructs a new URLClassLoader instance. The newly created instance will have the system ClassLoader as its parent. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters

urls	the list of URLs where a specific class or file could be found.

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader()` method doesn't allow creation of new ClassLoaders.

public URLClassLoader (URL[] urls, ClassLoader parent)

Since: API Level 1

Constructs a new URLClassLoader instance. The newly created instance will have the system ClassLoader as its parent. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters

urls	the list of URLs where a specific class or file could be found.
parent	the class loader to assign as this loader's parent.

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader()` method doesn't allow creation of new class loaders.

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

Since: API Level 1

Constructs a new URLClassLoader instance. The newly created instance will have the specified ClassLoader as its parent and use the specified factory to create stream handlers. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters

searchUrls	the list of URLs where a specific class or file could be found.
parent	the `ClassLoader` to assign as this loader's parent.
factory	the factory that will be used to create protocol-specific stream handlers.

Throws

SecurityException	if a security manager exists and its `checkCreateClassLoader()` method doesn't allow creation of new `ClassLoader`s.

Public Methods

public URL findResource (String name)

Since: API Level 1

Returns an URL referencing the specified resource or null if the resource could not be found.

Parameters

name	the name of the requested resource.

Returns

the URL which points to the given resource.

public Enumeration<URL> findResources (String name)

Since: API Level 1

Returns all known URLs which point to the specified resource.

Parameters

name	the name of the requested resource.

Returns

the enumeration of URLs which point to the specified resource.

Throws

IOException	if an I/O error occurs while attempting to connect.

public URL[] getURLs ()

Since: API Level 1

Returns the search list of this URLClassLoader.

Returns

the list of all known URLs of this instance.

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

Since: API Level 1

Returns a new URLClassLoader instance for the given URLs and the specified ClassLoader as its parent. The method loadClass() of the new instance will call the SecurityManager's checkPackageAccess() before loading a class.

Parameters

urls	the list of URLs that is passed to the new URLClassloader.
parentCl	the parent class loader that is passed to the new URLClassloader.

Returns

the created URLClassLoader instance.

public static URLClassLoader newInstance (URL[] urls)

Since: API Level 1

Returns a new URLClassLoader instance for the given URLs and the system ClassLoader as its parent. The method loadClass() of the new instance will call SecurityManager.checkPackageAccess() before loading a class.

Parameters

urls	the list of URLs that is passed to the new `URLClassloader`.

Returns

the created URLClassLoader instance.

Protected Methods

protected void addURL (URL url)

Since: API Level 1

Adds the specified URL to the search list.

Parameters

url	the URL which is to add.

protected Package definePackage (String packageName, Manifest manifest, URL url)

Since: API Level 1

Defines a new package using the information extracted from the specified manifest.

Parameters

packageName	the name of the new package.
manifest	the manifest containing additional information for the new package.
url	the URL to the code source for the new package.

Returns

the created package.

Throws

IllegalArgumentException	if a package with the given name already exists.

protected Class<?> findClass (String clsName)

Since: API Level 1

Tries to locate and load the specified class using the known URLs. If the class could be found, a class object representing the loaded class will be returned.

Parameters

clsName	the name of the class which has to be found.

Returns

the class that has been loaded.

Throws

ClassNotFoundException	if the specified class cannot be loaded.

protected PermissionCollection getPermissions (CodeSource codesource)

Since: API Level 1

Gets all permissions for the specified codesource. First, this method retrieves the permissions from the system policy. If the protocol is "file:/" then a new permission, FilePermission, granting the read permission to the file is added to the permission collection. Otherwise, connecting to and accepting connections from the URL is granted.

Parameters

codesource	the code source object whose permissions have to be known.

Returns

the list of permissions according to the code source object.

Interfaces

Classes

Enums

Exceptions

URLClassLoader

Class Overview

Summary

Public Constructors

public URLClassLoader (URL[] urls)

Parameters

Throws

public URLClassLoader (URL[] urls, ClassLoader parent)

Parameters

Throws

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

Parameters

Throws

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 parentCl)

Parameters

Returns

public static URLClassLoader newInstance (URL[] urls)

Parameters

Returns

Protected Methods

protected void addURL (URL url)

Parameters

protected Package definePackage (String packageName, Manifest manifest, URL url)

Parameters

Returns

Throws

protected Class<?> findClass (String clsName)

Parameters

Returns

Throws

protected PermissionCollection getPermissions (CodeSource codesource)

Parameters

Returns