java.lang.SecurityManager

Direct Known Subclasses:: RMISecurityManager

public class SecurityManager
extends Object

The security manager is a class that allows applications to implement a security policy. It allows an application to determine, before performing a possibly unsafe or sensitive operation, what the operation is and whether it is being attempted in a security context that allows the operation to be performed. The application can allow or disallow the operation.

The SecurityManager class contains many methods with names that begin with the word check. These methods are called by various methods in the Java libraries before those methods perform certain potentially sensitive operations. The invocation of such a check method typically looks like this:

     SecurityManager security = System.getSecurityManager();
     if (security != null) {
         security.checkXXX(argument,  . . . );
     }

The security manager is thereby given an opportunity to prevent completion of the operation by throwing an exception. A security manager routine simply returns if the operation is permitted, but throws a SecurityException if the operation is not permitted.

Environments using a security manager will typically set the security manager at startup. In the JDK implementation, this is done by setting the system property java.security.manager on the command line to the class name of the security manager. It can also be set to the empty String ("") or the special token "default" to use the default java.lang.SecurityManager. If a class name is specified, it must be java.lang.SecurityManager or a public subclass and have a public no-arg constructor. The class is loaded by the built-in system class loader if it is not java.lang.SecurityManager. If the java.security.manager system property is not set, the default value is null, which means a security manager will not be set at startup.

The Java run-time may also allow, but is not required to allow, the security manager to be set dynamically by invoking the setSecurityManager method. In the JDK implementation, if the Java virtual machine is started with the java.security.manager system property set to the special token "disallow" then a security manager will not be set at startup and cannot be set dynamically (the setSecurityManager method will throw an UnsupportedOperationException). If the java.security.manager system property is not set or is set to the special token "allow", then a security manager will not be set at startup but can be set dynamically. Finally, if the java.security.manager system property is set to the class name of the security manager, or to the empty String ("") or the special token "default", then a security manager is set at startup (as described previously) and can also be subsequently replaced (or disabled) dynamically (subject to the policy of the currently installed security manager). The following table illustrates the behavior of the JDK implementation for the different settings of the java.security.manager system property:

property value, the SecurityManager set at startup, can dynamically set a SecurityManager
Property Value	The SecurityManager set at startup	System.setSecurityManager run-time behavior
null	None	Success or throws `SecurityException` if not permitted by the currently installed security manager
empty String ("")	`java.lang.SecurityManager`	Success or throws `SecurityException` if not permitted by the currently installed security manager
"default"	`java.lang.SecurityManager`	Success or throws `SecurityException` if not permitted by the currently installed security manager
"disallow"	None	Always throws `UnsupportedOperationException`
"allow"	None	Success or throws `SecurityException` if not permitted by the currently installed security manager
a class name	the named class	Success or throws `SecurityException` if not permitted by the currently installed security manager

A future release of the JDK may change the default value of the java.security.manager system property to "disallow".

The current security manager is returned by the getSecurityManager method.

The special method checkPermission(java.security.Permission) determines whether an access request indicated by a specified permission should be granted or denied. The default implementation calls

   AccessController.checkPermission(perm);

If a requested access is allowed, checkPermission returns quietly. If denied, a SecurityException is thrown.

The default implementation of each of the other check methods in SecurityManager is to call the SecurityManager checkPermission method to determine if the calling thread has permission to perform the requested operation.

Note that the checkPermission method with just a single permission argument always performs security checks within the context of the currently executing thread. Sometimes a security check that should be made within a given context will actually need to be done from within a different context (for example, from within a worker thread). The getSecurityContext method and the checkPermission method that includes a context argument are provided for this situation. The getSecurityContext method returns a "snapshot" of the current calling context. (The default implementation returns an AccessControlContext object.) A sample call is the following:

   Object context = null;
   SecurityManager sm = System.getSecurityManager();
   if (sm != null) context = sm.getSecurityContext();

The checkPermission method that takes a context object in addition to a permission makes access decisions based on that context, rather than on that of the current execution thread. Code within a different context can thus call that method, passing the permission and the previously-saved context object. A sample call, using the SecurityManager sm obtained as in the previous example, is the following:

   if (sm != null) sm.checkPermission(permission, context);

Permissions fall into these categories: File, Socket, Net, Security, Runtime, Property, AWT, Reflect, and Serializable. The classes managing these various permission categories are java.io.FilePermission, java.net.SocketPermission, java.net.NetPermission, java.security.SecurityPermission, java.lang.RuntimePermission, java.util.PropertyPermission, java.awt.AWTPermission, java.lang.reflect.ReflectPermission, and java.io.SerializablePermission.

All but the first two (FilePermission and SocketPermission) are subclasses of java.security.BasicPermission, which itself is an abstract subclass of the top-level class for permissions, which is java.security.Permission. BasicPermission defines the functionality needed for all permissions that contain a name that follows the hierarchical property naming convention (for example, "exitVM", "setFactory", "queuePrintJob", etc). An asterisk may appear at the end of the name, following a ".", or by itself, to signify a wildcard match. For example: "a.*" or "*" is valid, "*a" or "a*b" is not valid.

FilePermission and SocketPermission are subclasses of the top-level class for permissions (java.security.Permission). Classes like these that have a more complicated name syntax than that used by BasicPermission subclass directly from Permission rather than from BasicPermission. For example, for a java.io.FilePermission object, the permission name is the path name of a file (or directory).

Some of the permission classes have an "actions" list that tells the actions that are permitted for the object. For example, for a java.io.FilePermission object, the actions list (such as "read, write") specifies which actions are granted for the specified file (or for files in the specified directory).

Other permission classes are for "named" permissions - ones that contain a name but no actions list; you either have the named permission or you don't.

Note: There is also a java.security.AllPermission permission that implies all permissions. It exists to simplify the work of system administrators who might need to perform multiple tasks that require all (or numerous) permissions.

See Permissions in the Java Development Kit (JDK) for permission-related information. This document includes a table listing the various SecurityManager check methods and the permission(s) the default implementation of each such method requires. It also contains a table of the methods that require permissions, and for each such method tells which permission it requires.

Since:: 1.0
See Also:: ClassLoader, SecurityException, getSecurityManager, setSecurityManager, AccessController, AccessControlContext, AccessControlException, Permission, BasicPermission, FilePermission, SocketPermission, PropertyPermission, RuntimePermission, Policy, SecurityPermission, ProtectionDomain

Constructor Summary

Constructors

Constructor Description

SecurityManager()
Constructs a new SecurityManager.

Method Summary

Modifier and Type	Method	Description
`void`	`checkAccept(String host, int port)`	Throws a `SecurityException` if the calling thread is not permitted to accept a socket connection from the specified host and port number.
`void`	`checkAccess(Thread t)`	Throws a `SecurityException` if the calling thread is not allowed to modify the thread argument.
`void`	`checkAccess(ThreadGroup g)`	Throws a `SecurityException` if the calling thread is not allowed to modify the thread group argument.
`void`	`checkConnect(String host, int port)`	Throws a `SecurityException` if the calling thread is not allowed to open a socket connection to the specified host and port number.
`void`	`checkConnect(String host, int port, Object context)`	Throws a `SecurityException` if the specified security context is not allowed to open a socket connection to the specified host and port number.
`void`	`checkCreateClassLoader()`	Throws a `SecurityException` if the calling thread is not allowed to create a new class loader.
`void`	`checkDelete(String file)`	Throws a `SecurityException` if the calling thread is not allowed to delete the specified file.
`void`	`checkExec(String cmd)`	Throws a `SecurityException` if the calling thread is not allowed to create a subprocess.
`void`	`checkExit(int status)`	Throws a `SecurityException` if the calling thread is not allowed to cause the Java Virtual Machine to halt with the specified status code.
`void`	`checkLink(String lib)`	Throws a `SecurityException` if the calling thread is not allowed to dynamic link the library code specified by the string argument file.
`void`	`checkListen(int port)`	Throws a `SecurityException` if the calling thread is not allowed to wait for a connection request on the specified local port number.
`void`	`checkMulticast(InetAddress maddr)`	Throws a `SecurityException` if the calling thread is not allowed to use (join/leave/send/receive) IP multicast.
`void`	`checkMulticast(InetAddress maddr, byte ttl)`	Deprecated. Use #checkPermission(java.security.Permission) instead
`void`	`checkPackageAccess(String pkg)`	Throws a `SecurityException` if the calling thread is not allowed to access the specified package.
`void`	`checkPackageDefinition(String pkg)`	Throws a `SecurityException` if the calling thread is not allowed to define classes in the specified package.
`void`	`checkPermission(Permission perm)`	Throws a `SecurityException` if the requested access, specified by the given permission, is not permitted based on the security policy currently in effect.
`void`	`checkPermission(Permission perm, Object context)`	Throws a `SecurityException` if the specified security context is denied access to the resource specified by the given permission.
`void`	`checkPrintJobAccess()`	Throws a `SecurityException` if the calling thread is not allowed to initiate a print job request.
`void`	`checkPropertiesAccess()`	Throws a `SecurityException` if the calling thread is not allowed to access or modify the system properties.
`void`	`checkPropertyAccess(String key)`	Throws a `SecurityException` if the calling thread is not allowed to access the system property with the specified `key` name.
`void`	`checkRead(FileDescriptor fd)`	Throws a `SecurityException` if the calling thread is not allowed to read from the specified file descriptor.
`void`	`checkRead(String file)`	Throws a `SecurityException` if the calling thread is not allowed to read the file specified by the string argument.
`void`	`checkRead(String file, Object context)`	Throws a `SecurityException` if the specified security context is not allowed to read the file specified by the string argument.
`void`	`checkSecurityAccess(String target)`	Determines whether the permission with the specified permission target name should be granted or denied.
`void`	`checkSetFactory()`	Throws a `SecurityException` if the calling thread is not allowed to set the socket factory used by `ServerSocket` or `Socket`, or the stream handler factory used by `URL`.
`void`	`checkWrite(FileDescriptor fd)`	Throws a `SecurityException` if the calling thread is not allowed to write to the specified file descriptor.
`void`	`checkWrite(String file)`	Throws a `SecurityException` if the calling thread is not allowed to write to the file specified by the string argument.
`protected Class<?>[]`	`getClassContext()`	Returns the current execution stack as an array of classes.
`Object`	`getSecurityContext()`	Creates an object that encapsulates the current execution environment.
`ThreadGroup`	`getThreadGroup()`	Returns the thread group into which to instantiate any new thread being created at the time this is being called.

Methods declared in class java.lang.Object

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

Constructor Details
- SecurityManager
  
  public SecurityManager()
  
  Constructs a new SecurityManager.
  If there is a security manager already installed, this method first calls the security manager's checkPermission method with the RuntimePermission("createSecurityManager") permission to ensure the calling thread has permission to create a new security manager. This may result in throwing a SecurityException.
  
  Throws:
  
  SecurityException - if a security manager already exists and its checkPermission method doesn't allow creation of a new security manager.
  
  See Also:
  
  System.getSecurityManager(), checkPermission, RuntimePermission
Method Details
- getClassContext
  
  protected Class<?>[] getClassContext()
  
  Returns the current execution stack as an array of classes.
  The length of the array is the number of methods on the execution stack. The element at index 0 is the class of the currently executing method, the element at index 1 is the class of that method's caller, and so on.
  
  Returns:
  
  the execution stack.
- getSecurityContext
  
  public Object getSecurityContext()
  
  Creates an object that encapsulates the current execution environment. The result of this method is used, for example, by the three-argument checkConnect method and by the two-argument checkRead method. These methods are needed because a trusted method may be called on to read a file or open a socket on behalf of another method. The trusted method needs to determine if the other (possibly untrusted) method would be allowed to perform the operation on its own.
  The default implementation of this method is to return an AccessControlContext object.
  
  Returns:
  
  an implementation-dependent object that encapsulates sufficient information about the current execution environment to perform some security checks later.
  
  See Also:
  
  checkConnect, checkRead, AccessControlContext
- checkPermission
  
  public void checkPermission(Permission perm)
  
  Throws a SecurityException if the requested access, specified by the given permission, is not permitted based on the security policy currently in effect.
  This method calls AccessController.checkPermission with the given permission.
  
  Parameters:
  
  perm - the requested permission.
  
  Throws:
  
  SecurityException - if access is not permitted based on the current security policy.
  
  NullPointerException - if the permission argument is null.
  
  Since:
  
  1.2
- checkPermission
  
  public void checkPermission(Permission perm, Object context)
  
  Throws a SecurityException if the specified security context is denied access to the resource specified by the given permission. The context must be a security context returned by a previous call to getSecurityContext and the access control decision is based upon the configured security policy for that security context.
  If context is an instance of AccessControlContext then the AccessControlContext.checkPermission method is invoked with the specified permission.
  If context is not an instance of AccessControlContext then a SecurityException is thrown.
  
  Parameters:
  
  perm - the specified permission
  
  context - a system-dependent security context.
  
  Throws:
  
  SecurityException - if the specified security context is not an instance of AccessControlContext (e.g., is null), or is denied access to the resource specified by the given permission.
  
  NullPointerException - if the permission argument is null.
  
  Since:
  
  1.2
  
  See Also:
  
  getSecurityContext(), AccessControlContext.checkPermission(java.security.Permission)
- checkCreateClassLoader
  
  public void checkCreateClassLoader()
  
  Throws a SecurityException if the calling thread is not allowed to create a new class loader.
  This method calls checkPermission with the RuntimePermission("createClassLoader") permission.
  If you override this method, then you should make a call to super.checkCreateClassLoader at the point the overridden method would normally throw an exception.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to create a new class loader.
  
  See Also:
  
  ClassLoader(), checkPermission
- checkAccess
  
  public void checkAccess(Thread t)
  
  Throws a SecurityException if the calling thread is not allowed to modify the thread argument.
  This method is invoked for the current security manager by the stop, suspend, resume, setPriority, setName, and setDaemon methods of class Thread.
  If the thread argument is a system thread (belongs to the thread group with a null parent) then this method calls checkPermission with the RuntimePermission("modifyThread") permission. If the thread argument is not a system thread, this method just returns silently.
  Applications that want a stricter policy should override this method. If this method is overridden, the method that overrides it should additionally check to see if the calling thread has the RuntimePermission("modifyThread") permission, and if so, return silently. This is to ensure that code granted that permission (such as the JDK itself) is allowed to manipulate any thread.
  If this method is overridden, then super.checkAccess should be called by the first statement in the overridden method, or the equivalent security check should be placed in the overridden method.
  
  Parameters:
  
  t - the thread to be checked.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to modify the thread.
  
  NullPointerException - if the thread argument is null.
  
  See Also:
  
  resume, setDaemon, setName, setPriority, stop, suspend, checkPermission
- checkAccess
  
  public void checkAccess(ThreadGroup g)
  
  Throws a SecurityException if the calling thread is not allowed to modify the thread group argument.
  This method is invoked for the current security manager when a new child thread or child thread group is created, and by the setDaemon, setMaxPriority, stop, suspend, resume, and destroy methods of class ThreadGroup.
  If the thread group argument is the system thread group ( has a null parent) then this method calls checkPermission with the RuntimePermission("modifyThreadGroup") permission. If the thread group argument is not the system thread group, this method just returns silently.
  Applications that want a stricter policy should override this method. If this method is overridden, the method that overrides it should additionally check to see if the calling thread has the RuntimePermission("modifyThreadGroup") permission, and if so, return silently. This is to ensure that code granted that permission (such as the JDK itself) is allowed to manipulate any thread.
  If this method is overridden, then super.checkAccess should be called by the first statement in the overridden method, or the equivalent security check should be placed in the overridden method.
  
  Parameters:
  
  g - the thread group to be checked.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to modify the thread group.
  
  NullPointerException - if the thread group argument is null.
  
  See Also:
  
  destroy, resume, setDaemon, setMaxPriority, stop, suspend, checkPermission
- checkExit
  
  public void checkExit(int status)
  
  Throws a SecurityException if the calling thread is not allowed to cause the Java Virtual Machine to halt with the specified status code.
  This method is invoked for the current security manager by the exit method of class Runtime. A status of 0 indicates success; other values indicate various errors.
  This method calls checkPermission with the RuntimePermission("exitVM."+status) permission.
  If you override this method, then you should make a call to super.checkExit at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  status - the exit status.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to halt the Java Virtual Machine with the specified status.
  
  See Also:
  
  exit, checkPermission
- checkExec
  
  public void checkExec(String cmd)
  
  Throws a SecurityException if the calling thread is not allowed to create a subprocess.
  This method is invoked for the current security manager by the exec methods of class Runtime.
  This method calls checkPermission with the FilePermission(cmd,"execute") permission if cmd is an absolute path, otherwise it calls checkPermission with FilePermission("<<ALL FILES>>","execute").
  If you override this method, then you should make a call to super.checkExec at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  cmd - the specified system command.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to create a subprocess.
  
  NullPointerException - if the cmd argument is null.
  
  See Also:
  
  Runtime.exec(java.lang.String), Runtime.exec(java.lang.String, java.lang.String[]), Runtime.exec(java.lang.String[]), Runtime.exec(java.lang.String[], java.lang.String[]), checkPermission
- checkLink
  
  public void checkLink(String lib)
  
  Throws a SecurityException if the calling thread is not allowed to dynamic link the library code specified by the string argument file. The argument is either a simple library name or a complete filename.
  This method is invoked for the current security manager by methods load and loadLibrary of class Runtime.
  This method calls checkPermission with the RuntimePermission("loadLibrary."+lib) permission.
  If you override this method, then you should make a call to super.checkLink at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  lib - the name of the library.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to dynamically link the library.
  
  NullPointerException - if the lib argument is null.
  
  See Also:
  
  Runtime.load(java.lang.String), Runtime.loadLibrary(java.lang.String), checkPermission
- checkRead
  
  public void checkRead(FileDescriptor fd)
  
  Throws a SecurityException if the calling thread is not allowed to read from the specified file descriptor.
  This method calls checkPermission with the RuntimePermission("readFileDescriptor") permission.
  If you override this method, then you should make a call to super.checkRead at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  fd - the system-dependent file descriptor.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified file descriptor.
  
  NullPointerException - if the file descriptor argument is null.
  
  See Also:
  
  FileDescriptor, checkPermission
- checkRead
  
  public void checkRead(String file)
  
  Throws a SecurityException if the calling thread is not allowed to read the file specified by the string argument.
  This method calls checkPermission with the FilePermission(file,"read") permission.
  If you override this method, then you should make a call to super.checkRead at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  file - the system-dependent file name.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified file.
  
  NullPointerException - if the file argument is null.
  
  See Also:
  
  checkPermission
- checkRead
  
  public void checkRead(String file, Object context)
  
  Throws a SecurityException if the specified security context is not allowed to read the file specified by the string argument. The context must be a security context returned by a previous call to getSecurityContext.
  If context is an instance of AccessControlContext then the AccessControlContext.checkPermission method will be invoked with the FilePermission(file,"read") permission.
  If context is not an instance of AccessControlContext then a SecurityException is thrown.
  If you override this method, then you should make a call to super.checkRead at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  file - the system-dependent filename.
  
  context - a system-dependent security context.
  
  Throws:
  
  SecurityException - if the specified security context is not an instance of AccessControlContext (e.g., is null), or does not have permission to read the specified file.
  
  NullPointerException - if the file argument is null.
  
  See Also:
  
  getSecurityContext(), AccessControlContext.checkPermission(java.security.Permission)
- checkWrite
  
  public void checkWrite(FileDescriptor fd)
  
  Throws a SecurityException if the calling thread is not allowed to write to the specified file descriptor.
  This method calls checkPermission with the RuntimePermission("writeFileDescriptor") permission.
  If you override this method, then you should make a call to super.checkWrite at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  fd - the system-dependent file descriptor.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified file descriptor.
  
  NullPointerException - if the file descriptor argument is null.
  
  See Also:
  
  FileDescriptor, checkPermission
- checkWrite
  
  public void checkWrite(String file)
  
  Throws a SecurityException if the calling thread is not allowed to write to the file specified by the string argument.
  This method calls checkPermission with the FilePermission(file,"write") permission.
  If you override this method, then you should make a call to super.checkWrite at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  file - the system-dependent filename.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified file.
  
  NullPointerException - if the file argument is null.
  
  See Also:
  
  checkPermission
- checkDelete
  
  public void checkDelete(String file)
  
  Throws a SecurityException if the calling thread is not allowed to delete the specified file.
  This method is invoked for the current security manager by the delete method of class File.
  This method calls checkPermission with the FilePermission(file,"delete") permission.
  If you override this method, then you should make a call to super.checkDelete at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  file - the system-dependent filename.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to delete the file.
  
  NullPointerException - if the file argument is null.
  
  See Also:
  
  File.delete(), checkPermission
- checkConnect
  
  public void checkConnect(String host, int port)
  
  Throws a SecurityException if the calling thread is not allowed to open a socket connection to the specified host and port number.
  A port number of -1 indicates that the calling method is attempting to determine the IP address of the specified host name.
  This method calls checkPermission with the SocketPermission(host+":"+port,"connect") permission if the port is not equal to -1. If the port is equal to -1, then it calls checkPermission with the SocketPermission(host,"resolve") permission.
  If you override this method, then you should make a call to super.checkConnect at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  host - the host name port to connect to.
  
  port - the protocol port to connect to.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to open a socket connection to the specified host and port.
  
  NullPointerException - if the host argument is null.
  
  See Also:
  
  checkPermission
- checkConnect
  
  public void checkConnect(String host, int port, Object context)
  
  Throws a SecurityException if the specified security context is not allowed to open a socket connection to the specified host and port number.
  A port number of -1 indicates that the calling method is attempting to determine the IP address of the specified host name.
  If context is not an instance of AccessControlContext then a SecurityException is thrown.
  Otherwise, the port number is checked. If it is not equal to -1, the context's checkPermission method is called with a SocketPermission(host+":"+port,"connect") permission. If the port is equal to -1, then the context's checkPermission method is called with a SocketPermission(host,"resolve") permission.
  If you override this method, then you should make a call to super.checkConnect at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  host - the host name port to connect to.
  
  port - the protocol port to connect to.
  
  context - a system-dependent security context.
  
  Throws:
  
  SecurityException - if the specified security context is not an instance of AccessControlContext (e.g., is null), or does not have permission to open a socket connection to the specified host and port.
  
  NullPointerException - if the host argument is null.
  
  See Also:
  
  getSecurityContext(), AccessControlContext.checkPermission(java.security.Permission)
- checkListen
  
  public void checkListen(int port)
  
  Throws a SecurityException if the calling thread is not allowed to wait for a connection request on the specified local port number.
  This method calls checkPermission with the SocketPermission("localhost:"+port,"listen").
  If you override this method, then you should make a call to super.checkListen at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  port - the local port.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to listen on the specified port.
  
  See Also:
  
  checkPermission
- checkAccept
  
  public void checkAccept(String host, int port)
  
  Throws a SecurityException if the calling thread is not permitted to accept a socket connection from the specified host and port number.
  This method is invoked for the current security manager by the accept method of class ServerSocket.
  This method calls checkPermission with the SocketPermission(host+":"+port,"accept") permission.
  If you override this method, then you should make a call to super.checkAccept at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  host - the host name of the socket connection.
  
  port - the port number of the socket connection.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to accept the connection.
  
  NullPointerException - if the host argument is null.
  
  See Also:
  
  ServerSocket.accept(), checkPermission
- checkMulticast
  
  public void checkMulticast(InetAddress maddr)
  
  Throws a SecurityException if the calling thread is not allowed to use (join/leave/send/receive) IP multicast.
  This method calls checkPermission with the java.net.SocketPermission(maddr.getHostAddress(), "accept,connect") permission.
  If you override this method, then you should make a call to super.checkMulticast at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  maddr - Internet group address to be used.
  
  Throws:
  
  SecurityException - if the calling thread is not allowed to use (join/leave/send/receive) IP multicast.
  
  NullPointerException - if the address argument is null.
  
  Since:
  
  1.1
  
  See Also:
  
  checkPermission
- checkMulticast
  
  @Deprecated(since="1.4") public void checkMulticast(InetAddress maddr, byte ttl)
  
  Deprecated.
  Use #checkPermission(java.security.Permission) instead
  
  Throws a SecurityException if the calling thread is not allowed to use (join/leave/send/receive) IP multicast.
  This method calls checkPermission with the java.net.SocketPermission(maddr.getHostAddress(), "accept,connect") permission.
  If you override this method, then you should make a call to super.checkMulticast at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  maddr - Internet group address to be used.
  
  ttl - value in use, if it is multicast send. Note: this particular implementation does not use the ttl parameter.
  
  Throws:
  
  SecurityException - if the calling thread is not allowed to use (join/leave/send/receive) IP multicast.
  
  NullPointerException - if the address argument is null.
  
  Since:
  
  1.1
  
  See Also:
  
  checkPermission
- checkPropertiesAccess
  
  public void checkPropertiesAccess()
  
  Throws a SecurityException if the calling thread is not allowed to access or modify the system properties.
  This method is used by the getProperties and setProperties methods of class System.
  This method calls checkPermission with the PropertyPermission("*", "read,write") permission.
  If you override this method, then you should make a call to super.checkPropertiesAccess at the point the overridden method would normally throw an exception.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access or modify the system properties.
  
  See Also:
  
  System.getProperties(), System.setProperties(java.util.Properties), checkPermission
- checkPropertyAccess
  
  public void checkPropertyAccess(String key)
  
  Throws a SecurityException if the calling thread is not allowed to access the system property with the specified key name.
  This method is used by the getProperty method of class System.
  This method calls checkPermission with the PropertyPermission(key, "read") permission.
  If you override this method, then you should make a call to super.checkPropertyAccess at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  key - a system property key.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified system property.
  
  NullPointerException - if the key argument is null.
  
  IllegalArgumentException - if key is empty.
  
  See Also:
  
  System.getProperty(java.lang.String), checkPermission
- checkPrintJobAccess
  
  public void checkPrintJobAccess()
  
  Throws a SecurityException if the calling thread is not allowed to initiate a print job request.
  This method calls checkPermission with the RuntimePermission("queuePrintJob") permission.
  If you override this method, then you should make a call to super.checkPrintJobAccess at the point the overridden method would normally throw an exception.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to initiate a print job request.
  
  Since:
  
  1.1
  
  See Also:
  
  checkPermission
- checkPackageAccess
  
  public void checkPackageAccess(String pkg)
  
  Throws a SecurityException if the calling thread is not allowed to access the specified package.
  During class loading, this method may be called by the loadClass method of class loaders and by the Java Virtual Machine to ensure that the caller is allowed to access the package of the class that is being loaded.
  This method checks if the specified package starts with or equals any of the packages in the package.access Security Property. An implementation may also check the package against an additional list of restricted packages as noted below. If the package is restricted, checkPermission(Permission) is called with a RuntimePermission("accessClassInPackage."+pkg) permission.
  If this method is overridden, then super.checkPackageAccess should be called as the first line in the overridden method.
  
  Implementation Note:
  
  This implementation also restricts all non-exported packages of modules loaded by the platform class loader or its ancestors. A "non-exported package" refers to a package that is not exported to all modules. Specifically, it refers to a package that either is not exported at all by its containing module or is exported in a qualified fashion by its containing module.
  
  Parameters:
  
  pkg - the package name.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to access the specified package.
  
  NullPointerException - if the package name argument is null.
  
  See Also:
  
  loadClass, getProperty, checkPermission
- checkPackageDefinition
  
  public void checkPackageDefinition(String pkg)
  
  Throws a SecurityException if the calling thread is not allowed to define classes in the specified package.
  This method is called by the loadClass method of some class loaders.
  This method checks if the specified package starts with or equals any of the packages in the package.definition Security Property. An implementation may also check the package against an additional list of restricted packages as noted below. If the package is restricted, checkPermission(Permission) is called with a RuntimePermission("defineClassInPackage."+pkg) permission.
  If this method is overridden, then super.checkPackageDefinition should be called as the first line in the overridden method.
  
  Implementation Note:
  
  This implementation also restricts all non-exported packages of modules loaded by the platform class loader or its ancestors. A "non-exported package" refers to a package that is not exported to all modules. Specifically, it refers to a package that either is not exported at all by its containing module or is exported in a qualified fashion by its containing module.
  
  Parameters:
  
  pkg - the package name.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to define classes in the specified package.
  
  NullPointerException - if the package name argument is null.
  
  See Also:
  
  ClassLoader.loadClass(String, boolean), getProperty, checkPermission
- checkSetFactory
  
  public void checkSetFactory()
  
  Throws a SecurityException if the calling thread is not allowed to set the socket factory used by ServerSocket or Socket, or the stream handler factory used by URL.
  This method calls checkPermission with the RuntimePermission("setFactory") permission.
  If you override this method, then you should make a call to super.checkSetFactory at the point the overridden method would normally throw an exception.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission to specify a socket factory or a stream handler factory.
  
  See Also:
  
  setSocketFactory, setSocketImplFactory, setURLStreamHandlerFactory, checkPermission
- checkSecurityAccess
  
  public void checkSecurityAccess(String target)
  
  Determines whether the permission with the specified permission target name should be granted or denied.
  If the requested permission is allowed, this method returns quietly. If denied, a SecurityException is raised.
  This method creates a SecurityPermission object for the given permission target name and calls checkPermission with it.
  See the documentation for SecurityPermission for a list of possible permission target names.
  If you override this method, then you should make a call to super.checkSecurityAccess at the point the overridden method would normally throw an exception.
  
  Parameters:
  
  target - the target name of the SecurityPermission.
  
  Throws:
  
  SecurityException - if the calling thread does not have permission for the requested access.
  
  NullPointerException - if target is null.
  
  IllegalArgumentException - if target is empty.
  
  Since:
  
  1.1
  
  See Also:
  
  checkPermission
- getThreadGroup
  
  public ThreadGroup getThreadGroup()
  
  Returns the thread group into which to instantiate any new thread being created at the time this is being called. By default, it returns the thread group of the current thread. This should be overridden by a specific security manager to return the appropriate thread group.
  
  Returns:
  
  ThreadGroup that new threads are instantiated into
  
  Since:
  
  1.1
  
  See Also:
  
  ThreadGroup

Class SecurityManager

Constructor Summary

Method Summary

Methods declared in class java.lang.Object

Constructor Details

Method Details