SecurityManager checkPermission() Method

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Description

The java.lang.SecurityManager.checkPermission(Permission perm) method 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.

Declaration

Following is the declaration for java.lang.SecurityManager.checkPermission() method

public void checkPermission(Permission perm)

Parameters

perm − the requested permission.

Return Value

This method does not return a value.

Exception

• SecurityException − if access is not permitted based on the current security policy.

• NullPointerException − if the permission argument is null.

Example

Our examples require that the permissions for each command is blocked. A new policy file was set that allows only the creating and setting of our Security Manager. The file is in C:/java.policy and contains the following text −

grant {
   permission java.lang.RuntimePermission "setSecurityManager";
   permission java.lang.RuntimePermission "createSecurityManager";
   permission java.lang.RuntimePermission "usePolicy";
};

The following example shows the usage of lang.SecurityManager.checkPermission() method.

package com.tutorialspoint;

import java.io.FilePermission;

public class SecurityManagerDemo extends SecurityManager {

   public static void main(String[] args) {

      // set the policy file as the system securuty policy
      System.setProperty("java.security.policy", "file:/C:/java.policy");

      // create a security manager
      SecurityManagerDemo sm = new SecurityManagerDemo();

      // set the system security manager
      System.setSecurityManager(sm);

      // perform the check
      sm.checkPermission(new FilePermission("test.txt", "read,write"));

      // print a message if we passed the check
      System.out.println("Allowed!");
   }
}

Let us compile and run the above program, this will produce the following result −

Exception in thread "main" java.security.AccessControlException: access denied (java.io.FilePermission test.txt read,write)