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JavaTM 2 Platform Std. Ed. v1.4.0 |
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java.lang.Object | +--java.lang.ClassLoader | +--java.security.SecureClassLoader | +--java.net.URLClassLoader
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.
Constructor Summary | |
URLClassLoader(URL[] urls)
Constructs a new URLClassLoader for the specified URLs using the default delegation parent ClassLoader . |
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URLClassLoader(URL[] urls,
ClassLoader parent)
Constructs a new URLClassLoader for the given URLs. |
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URLClassLoader(URL[] urls,
ClassLoader parent,
URLStreamHandlerFactory factory)
Constructs a new URLClassLoader for the specified URLs, parent class loader, and URLStreamHandlerFactory. |
Method Summary | |
protected void |
addURL(URL url)
Appends the specified URL to the list of URLs to search for classes and resources. |
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 |
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. |
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 |
defineClass |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public URLClassLoader(URL[] urls, ClassLoader parent)
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.
urls
- the URLs from which to load classes and resourcesparent
- the parent class loader for delegation
SecurityException
- if a security manager exists and its
checkCreateClassLoader
method doesn't allow
creation of a class loader.SecurityManager.checkCreateClassLoader()
public URLClassLoader(URL[] urls)
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.
urls
- the URLs from which to load classes and resources
SecurityException
- if a security manager exists and its
checkCreateClassLoader
method doesn't allow
creation of a class loader.SecurityManager.checkCreateClassLoader()
public URLClassLoader(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)
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.
urls
- the URLs from which to load classes and resourcesparent
- the parent class loader for delegationfactory
- the URLStreamHandlerFactory to use when creating URLs
SecurityException
- if a security manager exists and its
checkCreateClassLoader
method doesn't allow
creation of a class loader.SecurityManager.checkCreateClassLoader()
Method Detail |
protected void addURL(URL url)
url
- the URL to be added to the search path of URLspublic URL[] getURLs()
protected Class findClass(String name) throws ClassNotFoundException
findClass
in class ClassLoader
name
- the name of the class
ClassNotFoundException
- if the class could not be foundprotected Package definePackage(String name, Manifest man, URL url) throws IllegalArgumentException
name
- the package nameman
- the Manifest containing package version and sealing
informationurl
- the code source url for the package, or null if none
IllegalArgumentException
- if the package name duplicates
an existing package either in this class loader or one
of its ancestorspublic URL findResource(String name)
findResource
in class ClassLoader
name
- the name of the resource
URL
for the resource, or null
if the resource could not be found.public Enumeration findResources(String name) throws IOException
findResources
in class ClassLoader
name
- the resource name
Enumeration
of URL
s
IOException
- if an I/O exception occursprotected PermissionCollection getPermissions(CodeSource codesource)
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 to connect to and accept connections from the URL's host is granted.
getPermissions
in class SecureClassLoader
codesource
- the codesource
public static URLClassLoader newInstance(URL[] urls, ClassLoader parent)
loadClass
method of the URLClassLoader
returned by this method will invoke the
SecurityManager.checkPackageAccess
method before
loading the class.
urls
- the URLs to search for classes and resourcesparent
- the parent class loader for delegation
public static URLClassLoader newInstance(URL[] urls)
loadClass
method of the URLClassLoader
returned by this method will invoke the
SecurityManager.checkPackageAccess
before
loading the class.
urls
- the URLs to search for classes and resources
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JavaTM 2 Platform Std. Ed. v1.4.0 |
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