URLClassLoader (Java Platform SE 7 ) (original) (raw)

java.lang.Object
- java.lang.ClassLoader
- - java.security.SecureClassLoader
    - - java.net.URLClassLoader
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
MLet

public class URLClassLoader
extends SecureClassLoader
implements Closeable
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.
Since:
1.2

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addURL(URL url) Appends the specified URL to the list of URLs to search for classes and resources.
void	close() Closes this URLClassLoader, so that it can no longer be used to load new classes or resources that are defined by this loader.
protected Package	definePackage(String name,Manifest man,URL url) Defines a new package by name in this ClassLoader.
protected Class<?>	findClass(String name) Finds and loads the class with the specified name from the URL search path.
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.
protected PermissionCollection	getPermissions(CodeSource codesource) Returns the permissions for the given codesource object.
InputStream	getResourceAsStream(String name) Returns an input stream for reading the specified resource.
URL[]	getURLs() Returns the search path of URLs for loading classes and resources.
static URLClassLoader	newInstance(URL[] urls) Creates a new instance of URLClassLoader for the specified URLs and default parent class loader.
static URLClassLoader	newInstance(URL[] urls,ClassLoader parent) Creates a new instance of URLClassLoader for the specified URLs and parent class loader.

   * ### Methods inherited from class java.security.[SecureClassLoader](../../java/security/SecureClassLoader.html "class in java.security")  
   `[defineClass](../../java/security/SecureClassLoader.html#defineClass%28java.lang.String,%20byte[],%20int,%20int,%20java.security.CodeSource%29), [defineClass](../../java/security/SecureClassLoader.html#defineClass%28java.lang.String,%20java.nio.ByteBuffer,%20java.security.CodeSource%29)`  
   * ### Methods inherited from class java.lang.[ClassLoader](../../java/lang/ClassLoader.html "class in java.lang")  
   `[clearAssertionStatus](../../java/lang/ClassLoader.html#clearAssertionStatus%28%29), [defineClass](../../java/lang/ClassLoader.html#defineClass%28byte[],%20int,%20int%29), [defineClass](../../java/lang/ClassLoader.html#defineClass%28java.lang.String,%20byte[],%20int,%20int%29), [defineClass](../../java/lang/ClassLoader.html#defineClass%28java.lang.String,%20byte[],%20int,%20int,%20java.security.ProtectionDomain%29), [defineClass](../../java/lang/ClassLoader.html#defineClass%28java.lang.String,%20java.nio.ByteBuffer,%20java.security.ProtectionDomain%29), [definePackage](../../java/lang/ClassLoader.html#definePackage%28java.lang.String,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20java.net.URL%29), [findLibrary](../../java/lang/ClassLoader.html#findLibrary%28java.lang.String%29), [findLoadedClass](../../java/lang/ClassLoader.html#findLoadedClass%28java.lang.String%29), [findSystemClass](../../java/lang/ClassLoader.html#findSystemClass%28java.lang.String%29), [getClassLoadingLock](../../java/lang/ClassLoader.html#getClassLoadingLock%28java.lang.String%29), [getPackage](../../java/lang/ClassLoader.html#getPackage%28java.lang.String%29), [getPackages](../../java/lang/ClassLoader.html#getPackages%28%29), [getParent](../../java/lang/ClassLoader.html#getParent%28%29), [getResource](../../java/lang/ClassLoader.html#getResource%28java.lang.String%29), [getResources](../../java/lang/ClassLoader.html#getResources%28java.lang.String%29), [getSystemClassLoader](../../java/lang/ClassLoader.html#getSystemClassLoader%28%29), [getSystemResource](../../java/lang/ClassLoader.html#getSystemResource%28java.lang.String%29), [getSystemResourceAsStream](../../java/lang/ClassLoader.html#getSystemResourceAsStream%28java.lang.String%29), [getSystemResources](../../java/lang/ClassLoader.html#getSystemResources%28java.lang.String%29), [loadClass](../../java/lang/ClassLoader.html#loadClass%28java.lang.String%29), [loadClass](../../java/lang/ClassLoader.html#loadClass%28java.lang.String,%20boolean%29), [registerAsParallelCapable](../../java/lang/ClassLoader.html#registerAsParallelCapable%28%29), [resolveClass](../../java/lang/ClassLoader.html#resolveClass%28java.lang.Class%29), [setClassAssertionStatus](../../java/lang/ClassLoader.html#setClassAssertionStatus%28java.lang.String,%20boolean%29), [setDefaultAssertionStatus](../../java/lang/ClassLoader.html#setDefaultAssertionStatus%28boolean%29), [setPackageAssertionStatus](../../java/lang/ClassLoader.html#setPackageAssertionStatus%28java.lang.String,%20boolean%29), [setSigners](../../java/lang/ClassLoader.html#setSigners%28java.lang.Class,%20java.lang.Object[]%29)`  
   * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang")  
   `[clone](../../java/lang/Object.html#clone%28%29), [equals](../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../java/lang/Object.html#finalize%28%29), [getClass](../../java/lang/Object.html#getClass%28%29), [hashCode](../../java/lang/Object.html#hashCode%28%29), [notify](../../java/lang/Object.html#notify%28%29), [notifyAll](../../java/lang/Object.html#notifyAll%28%29), [toString](../../java/lang/Object.html#toString%28%29), [wait](../../java/lang/Object.html#wait%28%29), [wait](../../java/lang/Object.html#wait%28long%29), [wait](../../java/lang/Object.html#wait%28long,%20int%29)`

Constructor Detail

 * #### URLClassLoader  
 public URLClassLoader([URL](../../java/net/URL.html "class in java.net")[] urls,  
               [ClassLoader](../../java/lang/ClassLoader.html "class in java.lang") 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](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkCreateClassLoader` method doesn't allow creation of a class loader.  
 See Also:  
 [SecurityManager.checkCreateClassLoader()](../../java/lang/SecurityManager.html#checkCreateClassLoader%28%29)  
 * #### URLClassLoader  
 public URLClassLoader([URL](../../java/net/URL.html "class in java.net")[] 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](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkCreateClassLoader` method doesn't allow creation of a class loader.  
 See Also:  
 [SecurityManager.checkCreateClassLoader()](../../java/lang/SecurityManager.html#checkCreateClassLoader%28%29)  
 * #### URLClassLoader  
 public URLClassLoader([URL](../../java/net/URL.html "class in java.net")[] urls,  
               [ClassLoader](../../java/lang/ClassLoader.html "class in java.lang") parent,  
               [URLStreamHandlerFactory](../../java/net/URLStreamHandlerFactory.html "interface in java.net") 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](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager exists and its`checkCreateClassLoader` method doesn't allow creation of a class loader.  
 See Also:  
 [SecurityManager.checkCreateClassLoader()](../../java/lang/SecurityManager.html#checkCreateClassLoader%28%29)

Method Detail

* #### getResourceAsStream  
public [InputStream](../../java/io/InputStream.html "class in java.io") getResourceAsStream([String](../../java/lang/String.html "class in java.lang") name)  
Returns an input stream for reading the specified resource. If this loader is closed, then any resources opened by this method will be closed.  
 The search order is described in the documentation for [ClassLoader.getResource(String)](../../java/lang/ClassLoader.html#getResource%28java.lang.String%29).  
**Overrides:**  
`[getResourceAsStream](../../java/lang/ClassLoader.html#getResourceAsStream%28java.lang.String%29)` in class `[ClassLoader](../../java/lang/ClassLoader.html "class in java.lang")`  
Parameters:  
`name` \- The resource name  
Returns:  
An input stream for reading the resource, or null if the resource could not be found  
Since:  
1.7  
* #### close  
public void close()  
           throws [IOException](../../java/io/IOException.html "class in java.io")  
Closes this URLClassLoader, so that it can no longer be used to load new classes or resources that are defined by this loader. Classes and resources defined by any of this loader's parents in the delegation hierarchy are still accessible. Also, any classes or resources that are already loaded, are still accessible.  
 In the case of jar: and file: URLs, it also closes any files that were opened by it. If another thread is loading a class when the `close` method is invoked, then the result of that load is undefined.  
 The method makes a best effort attempt to close all opened files, by catching [IOException](../../java/io/IOException.html "class in java.io")s internally. Unchecked exceptions and errors are not caught. Calling close on an already closed loader has no effect.  
**Specified by:**  
`[close](../../java/io/Closeable.html#close%28%29)` in interface `[Closeable](../../java/io/Closeable.html "interface in java.io")`  
**Specified by:**  
`[close](../../java/lang/AutoCloseable.html#close%28%29)` in interface `[AutoCloseable](../../java/lang/AutoCloseable.html "interface in java.lang")`  
Throws:  
`[IOException](../../java/io/IOException.html "class in java.io")` \- if closing any file opened by this class loader resulted in an IOException. Any such exceptions are caught internally. If only one is caught, then it is re-thrown. If more than one exception is caught, then the second and following exceptions are added as suppressed exceptions of the first one caught, which is then re-thrown.  
`[SecurityException](../../java/lang/SecurityException.html "class in java.lang")` \- if a security manager is set, and it denies[RuntimePermission](../../java/lang/RuntimePermission.html "class in java.lang")("closeClassLoader")  
Since:  
1.7  
* #### addURL  
protected void addURL([URL](../../java/net/URL.html "class in java.net") url)  
Appends the specified URL to the list of URLs to search for classes and resources.  
 If the URL specified is `null` or is already in the list of URLs, or if this loader is closed, then invoking this method has no effect.  
Parameters:  
`url` \- the URL to be added to the search path of URLs  
* #### getURLs  
public [URL](../../java/net/URL.html "class in java.net")[] 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.  
* #### findClass  
protected [Class](../../java/lang/Class.html "class in java.lang")<?> findClass([String](../../java/lang/String.html "class in java.lang") name)  
                      throws [ClassNotFoundException](../../java/lang/ClassNotFoundException.html "class in java.lang")  
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.  
**Overrides:**  
`[findClass](../../java/lang/ClassLoader.html#findClass%28java.lang.String%29)` in class `[ClassLoader](../../java/lang/ClassLoader.html "class in java.lang")`  
Parameters:  
`name` \- the name of the class  
Returns:  
the resulting class  
Throws:  
`[ClassNotFoundException](../../java/lang/ClassNotFoundException.html "class in java.lang")` \- if the class could not be found, or if the loader is closed.  
* #### definePackage  
protected [Package](../../java/lang/Package.html "class in java.lang") definePackage([String](../../java/lang/String.html "class in java.lang") name,  
                    [Manifest](../../java/util/jar/Manifest.html "class in java.util.jar") man,  
                    [URL](../../java/net/URL.html "class in java.net") url)  
                         throws [IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")  
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](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the package name duplicates an existing package either in this class loader or one of its ancestors  
* #### findResource  
public [URL](../../java/net/URL.html "class in java.net") findResource([String](../../java/lang/String.html "class in java.lang") name)  
Finds the resource with the specified name on the URL search path.  
**Overrides:**  
`[findResource](../../java/lang/ClassLoader.html#findResource%28java.lang.String%29)` in class `[ClassLoader](../../java/lang/ClassLoader.html "class in java.lang")`  
Parameters:  
`name` \- the name of the resource  
Returns:  
a `URL` for the resource, or `null` if the resource could not be found, or if the loader is closed.  
* #### findResources  
public [Enumeration](../../java/util/Enumeration.html "interface in java.util")<[URL](../../java/net/URL.html "class in java.net")> findResources([String](../../java/lang/String.html "class in java.lang") name)  
                               throws [IOException](../../java/io/IOException.html "class in java.io")  
Returns an Enumeration of URLs representing all of the resources on the URL search path having the specified name.  
**Overrides:**  
`[findResources](../../java/lang/ClassLoader.html#findResources%28java.lang.String%29)` in class `[ClassLoader](../../java/lang/ClassLoader.html "class in java.lang")`  
Parameters:  
`name` \- the resource name  
Returns:  
an `Enumeration` of `URL`s If the loader is closed, the Enumeration will be empty.  
Throws:  
`[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O exception occurs  
* #### getPermissions  
protected [PermissionCollection](../../java/security/PermissionCollection.html "class in java.security") getPermissions([CodeSource](../../java/security/CodeSource.html "class in java.security") 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 there is an authority component, then permission to connect to and accept connections from that authority may be granted. 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.  
**Overrides:**  
`[getPermissions](../../java/security/SecureClassLoader.html#getPermissions%28java.security.CodeSource%29)` in class `[SecureClassLoader](../../java/security/SecureClassLoader.html "class in java.security")`  
Parameters:  
`codesource` \- the codesource  
Returns:  
the permissions granted to the codesource  
* #### newInstance  
public static [URLClassLoader](../../java/net/URLClassLoader.html "class in java.net") newInstance([URL](../../java/net/URL.html "class in java.net")[] urls,  
                         [ClassLoader](../../java/lang/ClassLoader.html "class in java.lang") 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  
* #### newInstance  
public static [URLClassLoader](../../java/net/URLClassLoader.html "class in java.net") newInstance([URL](../../java/net/URL.html "class in java.net")[] 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

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URLClassLoader (Java Platform SE 7 ) (original) (raw)

Constructor Summary

Method Summary

Constructor Detail

Method Detail