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 default parent class loader for delegation.
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 java.lang.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

Methods declared in class java.lang.Object

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

Constructor Details

SecureClassLoader

protected SecureClassLoader(ClassLoader parent)

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

Parameters:

parent - the parent ClassLoader

SecureClassLoader

protected SecureClassLoader()

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

SecureClassLoader

protected SecureClassLoader(String name,
 ClassLoader parent)

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

Parameters:

name - class loader name; or null if not named

parent - the parent 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.