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java.lang.Object | +----java.lang.SecurityManager
 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. The only exception to this convention is 
 checkTopLevelWindow, which returns a 
 boolean value. 
 
 The current security manager is set by the 
 setSecurityManager method in class 
 System. The current security manager is obtained 
 by the getSecurityManager method. 
 
 The default implementation of each of the 
 checkXXX methods is to assume that the caller 
 does not have permission to perform the requested operation.
true if there is a security check in 
 progress; false otherwise.
SecurityManager.
SecurityException if the 
 calling thread is not permitted to accept a socket connection from 
 the specified host and port number.
  SecurityException if the 
 calling thread is not allowed to modify the thread argument.
  SecurityException if the 
 calling thread is not allowed to modify the thread group argument.
  SecurityException if the 
 calling thread is not allowed to open a socket connection to the 
 specified host and port number.
  SecurityException if the 
 specified security context is not allowed to open a socket 
 connection to the specified host and port number.
  SecurityException if the 
 calling thread is not allowed to create a new class loader.
  SecurityException if the 
 calling thread is not allowed to delete the specified file.
  SecurityException if the 
 calling thread is not allowed to create a subprocess.
  SecurityException if the 
 calling thread is not allowed to cause the Java Virtual Machine to 
 halt with the specified status code.
  SecurityException if the 
 calling thread is not allowed to dynamic link the library code 
 specified by the string argument file.
  SecurityException if the 
 calling thread is not allowed to wait for a connection request on 
 the specified local port number.
  SecurityException if the 
 calling thread is not allowed to access the package specified by 
 the argument.
  SecurityException if the 
 calling thread is not allowed to define classes in the package 
 specified by the argument.
  SecurityException if the 
 calling thread is not allowed to access or modify the system 
 properties.
  SecurityException if the 
 calling thread is not allowed to access the system property with 
 the specified key name.
  SecurityException if the 
 calling thread is not allowed to read from the specified file 
 descriptor.
  SecurityException if the 
 calling thread is not allowed to read the file specified by the 
 string argument.
  SecurityException if the 
 specified security context is not allowed to read the file 
 specified by the string argument.
  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.
  false if the calling 
 thread is not trusted to bring up the top-level window indicated 
 by the window argument.
  SecurityException if the 
 calling thread is not allowed to write to the specified file 
 descriptor.
  SecurityException if the 
 calling thread is not allowed to write to the file specified by 
 the string argument.
  null.
protected boolean inCheck
true if there is a security check in 
 progress; false otherwise.
protected SecurityManager()
SecurityManager. An application is 
 not allowed to create a new security manager if there is already a 
 current security manager.
public boolean getInCheck()
inCheck field. This field should
          contain true if a security check is in progress;
          false otherwise.
    protected native Class[] getClassContext()
 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.
protected native ClassLoader currentClassLoader()
null if there is no occurrence on the
          stack of a method from a class defined using a class loader.
  protected Class currentLoadedClass()
protected native int classDepth(String name)
-1 if such a frame cannot be found.
  protected native int classLoaderDepth()
-1 if there is no occurrence of a method from
          a class defined using a class loader.
  protected boolean inClass(String name)
true if a method from a class with the specified
          name is on the execution stack; false otherwise.
  protected boolean inClassLoader()
null.
true if a method from a class defined using a
          class loader is on the execution stack.
  public Object getSecurityContext()
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.
public void checkCreateClassLoader()
SecurityException if the 
 calling thread is not allowed to create a new class loader. 
 
 The checkCreateClassLoader method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkAccess(Thread g)
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. 
 
 The checkAccess method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkAccess(ThreadGroup g)
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. 
 
 The checkAccess method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkExit(int status)
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. 
 
 The checkExit method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkExec(String cmd)
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.
 
 The checkExec method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkLink(String lib)
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. 
 
 The checkLink method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkRead(FileDescriptor fd)
SecurityException if the 
 calling thread is not allowed to read from the specified file 
 descriptor. 
 
 The checkRead method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkRead(String file)
SecurityException if the 
 calling thread is not allowed to read the file specified by the 
 string argument. 
 
 The checkRead method for class 
 SecurityManager always throws a 
 SecurityException.
 public void checkRead(String file,
                       Object context)
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. 
 
 The checkRead method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkWrite(FileDescriptor fd)
SecurityException if the 
 calling thread is not allowed to write to the specified file 
 descriptor. 
 
 The checkWrite method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkWrite(String file)
SecurityException if the 
 calling thread is not allowed to write to the file specified by 
 the string argument. 
 
 The checkWrite method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkDelete(String file)
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.
 
 The checkDelete method for class 
 SecurityManager always throws a 
 SecurityException.
 public void checkConnect(String host,
                          int port)
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. 
 
 The checkConnect method for class 
 SecurityManager always throws a 
 SecurityException.
host and port.
  
 public void checkConnect(String host,
                          int port,
                          Object context)
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. 
 
 The checkConnect method for class 
 SecurityManager always throws a 
 SecurityException.
host and port.
    public void checkListen(int port)
SecurityException if the 
 calling thread is not allowed to wait for a connection request on 
 the specified local port number. 
 
 The checkListen method for class 
 SecurityManager always throws a 
 SecurityException.
 public void checkAccept(String host,
                         int port)
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. 
 
 The checkAccept method for class 
 SecurityManager always throws a
 SecurityException.
public void checkMulticast(InetAddress maddr)
 public void checkMulticast(InetAddress maddr,
                            byte ttl)
public void checkPropertiesAccess()
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. 
 
 The checkPropertiesAccess method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkPropertyAccess(String key)
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. 
 
 The checkPropertiesAccess method for class 
 SecurityManager always throws a 
 SecurityException.
public boolean checkTopLevelWindow(Object window)
false if the calling 
 thread is not trusted to bring up the top-level window indicated 
 by the window argument. In this case, the caller can 
 still decide to show the window, but the window should include 
 some sort of visual warning. If the method returns 
 true, then the window can be shown without any 
 special restrictions. 
 
 See class Window for more information on trusted and 
 untrusted windows. 
 
 The checkSetFactory method for class 
 SecurityManager always returns false.
true if the caller is trusted to put up
             top-level windows; false otherwise.
    public void checkPrintJobAccess()
public void checkSystemClipboardAccess()
public void checkAwtEventQueueAccess()
public void checkPackageAccess(String pkg)
SecurityException if the 
 calling thread is not allowed to access the package specified by 
 the argument. 
 
 This method is used by the loadClass method of class 
 loaders. 
 
 The checkPackageAccess method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkPackageDefinition(String pkg)
SecurityException if the 
 calling thread is not allowed to define classes in the package 
 specified by the argument. 
 
 This method is used by the loadClass method of some 
 class loaders. 
 
 The checkPackageDefinition method for class 
 SecurityManager always throws a 
 SecurityException.
public void checkSetFactory()
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. 
 
 The checkSetFactory method for class 
 SecurityManager always throws a 
 SecurityException.
 public void checkMemberAccess(Class clazz,
                               int which)
public void checkSecurityAccess(String action)
public ThreadGroup getThreadGroup()
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