JavaTM 2 Platform
Std. Ed. v1.4.2
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java.lang
Class SecurityManager



public class SecurityManager
extends
   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 2 SDK for permission-related information. This document includes, for example, 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 all the version 1.2 methods that require permissions, and for each such method tells which permission it requires.

For more information about SecurityManager changes made in the Java 2 SDK and advice regarding porting of 1.1-style security managers, see the security documentation.

Since:
JDK1.0
See Also:
SecurityException, checkTopLevelWindow, getSecurityManager, setSecurityManager, AccessControlContext, Permission, FilePermission, PropertyPermission, AWTPermission, SecurityPermission,

Field Summary
protected  boolean inCheck
          Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.
 
Constructor Summary
SecurityManager()
          Constructs a new SecurityManager.
 
Method Summary
 void checkAccept(  void checkAccess(  void checkAccess(  void checkAwtEventQueueAccess()
          Throws a SecurityException if the calling thread is not allowed to access the AWT event queue.
 void checkConnect(  void checkConnect(
          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(  void checkExec(  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(  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 checkMemberAccess(  void checkMulticast(  void checkMulticast(  void checkPackageAccess(  void checkPackageDefinition(  void checkPermission(  void checkPermission(
          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(  void checkRead(  void checkRead(  void checkRead(
          Throws a SecurityException if the specified security context is not allowed to read the file specified by the string argument.
 void checkSecurityAccess(  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 checkSystemClipboardAccess()
          Throws a SecurityException if the calling thread is not allowed to access the system clipboard.
 boolean checkTopLevelWindow(  void checkWrite(  void checkWrite( protected  int classDepth( protected  int classLoaderDepth()
          Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.
protected   protected   protected    boolean getInCheck()
          Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.
    protected  boolean inClass( protected  boolean inClassLoader()
          Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.
 
Methods inherited from class java.lang. clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

inCheck

protected boolean inCheck
Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.

This field is true if there is a security check in progress; false otherwise.

Constructor Detail

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:
RuntimePermission
Method Detail

getInCheck

public boolean getInCheck()
Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.

Tests if there is a security check in progress.

Returns:
the value of the inCheck field. This field should contain true if a security check is in progress, false otherwise.
See Also:
inCheck

getClassContext

protected 

currentClassLoader

protected AccessController.doPrivileged(java.security.PrivilegedAction))
   are from classes
   defined using the system class loader or one of its ancestors.

   
  • A call to checkPermission with java.security.AllPermission does not result in a SecurityException.
  • Returns:
    the class loader of the most recent occurrence on the stack of a method from a class defined using a non-system class loader.
    See Also:
    getSystemClassLoader, checkPermission

    currentLoadedClass

    protected AccessController.doPrivileged(java.security.PrivilegedAction))
       are from classes
       defined using the system class loader or one of its ancestors.
    
       
  • A call to checkPermission with java.security.AllPermission does not result in a SecurityException.
  • Returns:
    the class of the most recent occurrence on the stack of a method from a class defined using a non-system class loader.
    See Also:
    getSystemClassLoader, checkPermission

    classDepth

    protected int classDepth(

    classLoaderDepth

    protected int classLoaderDepth()
    Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.

    Returns the stack depth of the most recently executing method from a class defined using a non-system class loader. A non-system class loader is defined as being a class loader that is not equal to the system class loader (as returned by ClassLoader.getSystemClassLoader()) or one of its ancestors.

    This method will return -1 in the following three cases:

    1. All methods on the execution stack are from classes defined using the system class loader or one of its ancestors.
    2. All methods on the execution stack up to the first "privileged" caller (see AccessController.doPrivileged(java.security.PrivilegedAction)) are from classes defined using the system class loader or one of its ancestors.
    3. A call to checkPermission with java.security.AllPermission does not result in a SecurityException.

    Returns:
    the depth on the stack frame of the most recent occurrence of a method from a class defined using a non-system class loader.
    See Also:
    getSystemClassLoader, checkPermission

    inClass

    protected boolean inClass(

    inClassLoader

    protected boolean inClassLoader()
    Deprecated. This type of security checking is not recommended. It is recommended that the checkPermission call be used instead.

    Basically, tests if a method from a class defined using a class loader is on the execution stack.

    Returns:
    true if a call to currentClassLoader has a non-null return value.
    See Also:
    currentClassLoader

    getSecurityContext

    public AccessControlContext
    
    

    checkPermission

    public void checkPermission( - if access is not permitted based on
    		  the current security policy.
    

    checkPermission

    public void checkPermission(
    
    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:
    - 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:

    checkAccess

    public void checkAccess( 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 SDK 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:
    - if the thread argument is null.
    See Also:
    resume, setDaemon, setName, setPriority, stop, suspend, checkPermission

    checkAccess

    public void checkAccess( 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 SDK 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:
    - 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") 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:

    checkExec

    public void checkExec( 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:
    - 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( 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:
    - if the lib argument is null.
    See Also:
    Runtime.load(java.lang.String), Runtime.loadLibrary(java.lang.String), checkPermission

    checkRead

    public void checkRead(
     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:
    - if the file descriptor argument is null.
    See Also:

    checkRead

    public void checkRead( 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:
    - if the file argument is null.
    See Also:
    checkPermission

    checkRead

    public void checkRead(
    
    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:
    - if the file argument is null.
    See Also:
    getSecurityContext(), AccessControlContext.checkPermission(java.security.Permission)

    checkWrite

    public void checkWrite(
     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:
    - if the file descriptor argument is null.
    See Also:

    checkWrite

    public void checkWrite( 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:
    - if the file argument is null.
    See Also:
    checkPermission

    checkDelete

    public void checkDelete( 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:
    - if the file argument is null.
    See Also:
    File.delete(), checkPermission

    checkConnect

    public void checkConnect( 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:
    - if the host argument is null.
    See Also:
    checkPermission

    checkConnect

    public void checkConnect(
    
    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:
    - 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.

    If port is not 0, this method calls checkPermission with the SocketPermission("localhost:"+port,"listen"). If port is zero, this method calls checkPermission with SocketPermission("localhost:1024-","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:

    checkAccept

    public void checkAccept( 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:
    - if the host argument is null.
    See Also:
    ServerSocket.accept(), checkPermission

    checkMulticast

    public void checkMulticast( 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:
    - if the address argument is null.
    Since:
    JDK1.1
    See Also:
    checkPermission

    checkMulticast

    public void checkMulticast( 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:
    - if the address argument is null.
    Since:
    JDK1.1
    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:

    checkPropertyAccess

    public void checkPropertyAccess( 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:
    - if the key argument is null.

    checkTopLevelWindow

    public boolean checkTopLevelWindow( permission,
     and returns true if a SecurityException is not thrown,
     otherwise it returns false.
     

    If you override this method, then you should make a call to super.checkTopLevelWindow at the point the overridden method would normally return false, and the value of super.checkTopLevelWindow should be returned.

    Parameters:
    window - the new window that is being created.
    Returns:
    true if the calling thread is trusted to put up top-level windows; false otherwise.
    Throws:
    Window, 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:

    checkSystemClipboardAccess

    public void checkSystemClipboardAccess()
    Throws a SecurityException if the calling thread is not allowed to access the system clipboard.

    This method calls checkPermission with the AWTPermission("accessClipboard") permission.

    If you override this method, then you should make a call to super.checkSystemClipboardAccess at the point the overridden method would normally throw an exception.

    Throws:

    checkAwtEventQueueAccess

    public void checkAwtEventQueueAccess()
    Throws a SecurityException if the calling thread is not allowed to access the AWT event queue.

    This method calls checkPermission with the AWTPermission("accessEventQueue") permission.

    If you override this method, then you should make a call to super.checkAwtEventQueueAccess at the point the overridden method would normally throw an exception.

    Throws:

    checkPackageAccess

    public void checkPackageAccess(,
     and checks to see if pkg starts with or equals
     any of the restricted packages. If it does, then
     checkPermission gets called with the
     RuntimePermission("accessClassInPackage."+pkg)
     permission.
     

    If this method is overridden, then super.checkPackageAccess should be called as the first line in the overridden method.

    Parameters:
    pkg - the package name.
    Throws:
    - if the package name argument is null.
    See Also:
    loadClass, getProperty, checkPermission

    checkPackageDefinition

    public void checkPackageDefinition(,
     and checks to see if pkg starts with or equals
     any of the restricted packages. If it does, then
     checkPermission gets called with the
     RuntimePermission("defineClassInPackage."+pkg)
     permission.
     

    If this method is overridden, then super.checkPackageDefinition should be called as the first line in the overridden method.

    Parameters:
    pkg - the package name.
    Throws:

    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:

    checkMemberAccess

    public void checkMemberAccess( permission.
     

    If this method is overridden, then a call to super.checkMemberAccess cannot be made, as the default implementation of checkMemberAccess relies on the code being checked being at a stack depth of 4.

    Parameters:
    clazz - the class that reflection is to be performed on.
    which - type of access, PUBLIC or DECLARED.
    Throws:
    - if the clazz argument is null.
    Since:
    JDK1.1
    See Also:

    checkSecurityAccess

    public void checkSecurityAccess(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:
    - if target is null.

    getThreadGroup

    public ThreadGroup

    JavaTM 2 Platform
    Std. Ed. v1.4.2
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    For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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