Class SecureClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

Direct Known Subclasses:

URLClassLoader

public class SecureClassLoader
extends ClassLoader

This class extends ClassLoader with additional support for defining classes with an associated code source and permissions.

API Note:

Permissions cannot be used for controlling access to resources as the Security Manager is no longer supported.

Since:

1.2

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SecureClassLoader()	Creates a new SecureClassLoader using the system class loader as the parent.
protected	SecureClassLoader(ClassLoader parent)	Creates a new SecureClassLoader using the specified parent class loader for delegation.
protected	SecureClassLoader(String name, ClassLoader parent)	Creates a new SecureClassLoader of the specified name and using the specified parent class loader for delegation.

Method Summary

Modifier and Type	Method	Description
protected final Class<?>	defineClass(String name, byte[] b, int off, int len, CodeSource cs)	Converts an array of bytes into an instance of class Class, with an optional CodeSource.
protected final Class<?>	defineClass(String name, ByteBuffer b, CodeSource cs)	Converts a ByteBuffer into an instance of class Class, with an optional CodeSource.
protected PermissionCollection	getPermissions(CodeSource codesource)	Returns the permissions for the given CodeSource object.

Methods declared in class ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Modifier and Type	Method	Description
void	clearAssertionStatus()	Clears the default, package and class assertion status of a classloader
protected final Class<?>	defineClass(byte[] classRep, int offset, int length)	Deprecated. Use defineClass(String, byte[], int, int)
protected 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.
protected 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 new class to the specified protection domain.
protected final Class<?>	defineClass(String name, ByteBuffer buffer, ProtectionDomain domain)	Constructs a new class from an array of bytes containing a class definition in class file format and assigns the new class to the specified protection domain.
protected Package	definePackage(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase)	Define a new Package using the specified information.
protected Class<?>	findClass(String className)	Overridden by subclasses, by default throws ClassNotFoundException.
protected Class<?>	findClass(String moduleName, String className)	Overridden by subclasses that support the loading from modules.
protected String	findLibrary(String libName)	Answers the absolute path of the file containing the library associated with the given name, or null.
protected final Class<?>	findLoadedClass(String className)	Attempts to find and return a class which has already been loaded by the virtual machine.
protected URL	findResource(String resName)	Answers an URL which can be used to access the resource described by resName, using the class loader's resource lookup algorithm.
protected URL	findResource(String moduleName, String resName)	Answers an URL which can be used to access the resource described by resName, using the class loader's resource lookup algorithm.
protected Enumeration<URL>	findResources(String resName)	Answers an Enumeration of URL which can be used to access the resources described by resName, using the class loader's resource lookup algorithm.
protected final Class<?>	findSystemClass(String className)	Attempts to load a class using the system class loader.
protected Object	getClassLoadingLock(String className)	Answers the lock object for class loading in parallel.
final Package	getDefinedPackage(String name)	Answers a package of given name defined by this ClassLoader.
final Package[]	getDefinedPackages()	Answers all the packages defined by this classloader.
String	getName()	Get the name given when creating the ClassLoader instance, or null if none was provided.
protected Package	getPackage(String name)	Deprecated. Use getDefinedPackage(String)
protected Package[]	getPackages()	Answers all the packages known to this class loader.
final ClassLoader	getParent()	Returns the specified ClassLoader's parent.
static ClassLoader	getPlatformClassLoader()	Return the Platform classloader.
URL	getResource(String resName)	Answers an URL which can be used to access the resource described by resName, using the class loader's resource lookup algorithm.
InputStream	getResourceAsStream(String resName)	Answers a stream on a resource found by looking up resName using the class loader's resource lookup algorithm.
Enumeration<URL>	getResources(String resName)	Answers an Enumeration of URL which can be used to access the resources described by resName, using the class loader's resource lookup algorithm.
static ClassLoader	getSystemClassLoader()	Convenience operation to obtain a reference to the system class loader.
static URL	getSystemResource(String resName)	Answers an URL specifying a resource which can be found by looking up resName using the system class loader's resource lookup algorithm.
static InputStream	getSystemResourceAsStream(String resName)	Answers a stream on a resource found by looking up resName using the system class loader's resource lookup algorithm.
static Enumeration<URL>	getSystemResources(String resName)	Answers an Enumeration of URL containing all resources which can be found by looking up resName using the system class loader's resource lookup algorithm.
final Module	getUnnamedModule()	Answers the unnamed Module of this class loader.
final boolean	isRegisteredAsParallelCapable()	Indicating if this class loader is registered as parallel capable or not
Class<?>	loadClass(String className)	Invoked by the Virtual Machine when resolving class references.
protected Class<?>	loadClass(String className, boolean resolveClass)	Attempts to load the type className in the running VM, optionally linking the type after a successful load.
protected static boolean	registerAsParallelCapable()	Attempts to register the ClassLoader as being capable of parallel class loading.
protected final void	resolveClass(Class<?> clazz)	Forces a class to be linked (initialized).
Stream<URL>	resources(String name)	Answers a stream of URL which can be used to access the resources described by name, using the class loader's resource lookup algorithm.
void	setClassAssertionStatus(String cname, boolean enable)	Sets the assertion status of a class.
void	setDefaultAssertionStatus(boolean enable)	Sets the default assertion status of a classloader
void	setPackageAssertionStatus(String pname, boolean enable)	Sets the assertion status of a package.
protected final void	setSigners(Class<?> c, Object[] signers)	Sets the signers of a class.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

SecureClassLoader

protected SecureClassLoader(ClassLoader parent)

Creates a new SecureClassLoader using the specified parent class loader for delegation.

API Note:

If parent is specified as null (for the bootstrap class loader) then there is no guarantee that all platform classes are visible. See Run-time Built-in Class Loaders for information on the bootstrap class loader and other built-in class loaders.

Parameters:

parent - the parent ClassLoader, can be null for the bootstrap class loader

SecureClassLoader

protected SecureClassLoader()

Creates a new SecureClassLoader using the system class loader as the parent.

SecureClassLoader

protected SecureClassLoader(String name,
 ClassLoader parent)

Creates a new SecureClassLoader of the specified name and using the specified parent class loader for delegation.

API Note:

If parent is specified as null (for the bootstrap class loader) then there is no guarantee that all platform classes are visible. See Run-time Built-in Class Loaders for information on the bootstrap class loader and other built-in class loaders.

Parameters:

name - class loader name; or null if not named

parent - the parent class loader, can be null for the bootstrap class loader

Throws:

IllegalArgumentException - if the given name is empty.

Since:

9

Method Details

defineClass

protected final Class<?> defineClass(String name,
 byte[] b,
 int off,
 int len,
 CodeSource cs)

Converts an array of bytes into an instance of class Class, with an optional CodeSource. Before the class can be used it must be resolved.

If a non-null CodeSource is supplied a ProtectionDomain is constructed and associated with the class being defined.

Parameters:

name - the expected name of the class, or null if not known, using '.' and not '/' as the separator and without a trailing ".class" suffix.

b - the bytes that make up the class data. The bytes in positions off through off+len-1 should have the format of a valid class file as defined by The Java Virtual Machine Specification.

off - the start offset in b of the class data

len - the length of the class data

cs - the associated CodeSource, or null if none

Returns:

the Class object created from the data, and optional CodeSource.

Throws:

ClassFormatError - if the data did not contain a valid class

IndexOutOfBoundsException - if either off or len is negative, or if off+len is greater than b.length.

SecurityException - if an attempt is made to add this class to a package that contains classes that were signed by a different set of certificates than this class, or if the class name begins with "java.".

defineClass

protected final Class<?> defineClass(String name,
 ByteBuffer b,
 CodeSource cs)

Converts a ByteBuffer into an instance of class Class, with an optional CodeSource. Before the class can be used it must be resolved.

If a non-null CodeSource is supplied a ProtectionDomain is constructed and associated with the class being defined.

Parameters:

name - the expected name of the class, or null if not known, using '.' and not '/' as the separator and without a trailing ".class" suffix.

b - the bytes that make up the class data. The bytes from positions b.position() through b.position() + b.limit() -1 should have the format of a valid class file as defined by The Java Virtual Machine Specification.

cs - the associated CodeSource, or null if none

Returns:

the Class object created from the data, and optional CodeSource.

Throws:

ClassFormatError - if the data did not contain a valid class

SecurityException - if an attempt is made to add this class to a package that contains classes that were signed by a different set of certificates than this class, or if the class name begins with "java.".

Since:

1.5

getPermissions

protected PermissionCollection getPermissions(CodeSource codesource)

Returns the permissions for the given CodeSource object.

This method is invoked by the defineClass method which takes a CodeSource as an argument when it is constructing the ProtectionDomain for the class being defined.

Parameters:

codesource - the codesource.

Returns:

the permissions for the codesource.