Class 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 which are retrieved by the system policy by default.

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

All Methods Instance Methods Concrete Methods
Modifier and Type Method Description
protected 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 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 Detail

SecureClassLoader

protected SecureClassLoader​(ClassLoader parent)

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

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:
parent - the parent ClassLoader
Throws:
SecurityException - if a security manager exists and its checkCreateClassLoader method doesn't allow creation of a class loader.
See Also:
SecurityManager.checkCreateClassLoader()

SecureClassLoader

protected SecureClassLoader()

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

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.

Throws:
SecurityException - if a security manager exists and its checkCreateClassLoader method doesn't allow creation of a class loader.
See Also:
SecurityManager.checkCreateClassLoader()

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.
SecurityException - if a security manager exists and its SecurityManager.checkCreateClassLoader() method doesn't allow creation of a class loader.
Since:
9

Method Detail

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 granted to the codesource.