java.rmi.RMISecurityManager Class in Java - GeeksforGeeks

16 Sep, 2021
The RMISecurityManager enforces the security policy for classes that are loaded as stubs for remote objects, by overriding all of the relevant access-check methods from the SecurityManager. By default, stub objects are only allowed to perform class definition and class access operations. 
Note: 
If the local security manager is not an RMISecurityManager using the System.setSecurityManager() method
Then stub classes will only be loadable from the local file system.
java.lang.Object
java.lang.SecurityManager
java.rmi.RMISecurityManager
Syntax:
public class RMISecurityManager 
extends SecurityManager
Note: A subclass of SecurityManager used by RMI applications that use downloaded code. 
RMI’s class loader will not download any classes from remote locations if no security manager has been set. RMISecurityManager does not apply to applets, which run under the protection of their browser’s security manager. RMISecurityManager implements a policy that is no different than the policy implemented by SecurityManager. Therefore an RMI application should use the SecurityManager class or another application-specific SecurityManager implementation instead of this class.
How to incorporate the Security Manager class? 
To use a SecurityManager in your application, add the following statement to your code (it needs to be executed before RMI can download code from remote hosts, so it most likely needs to appear in the main method of your application)
Syntax:
System.setSecurityManager(new SecurityManager());
RMISecurityManager implements a policy identical to the policy implemented by SecurityManager. RMI applications should use the SecurityManager class or another appropriate SecurityManager implementation instead of this class. RMI’s class loader will download classes from remote locations only if a security manager has been set.
Now let us move forward with the constructor of this class as follows:
RMISecurityManager(): Constructs a new RMISecurityManager
Implementation:
if (System.getSecurityManager() == null) 
{
    // Setting the RMISecurityManager on System
    System.setSecurityManager(new SecurityManager());
} 
Applets typically run in a container that already has a security manager, so there is generally no need for applets to set a security manager. If you have a standalone application, you might need to set a SecurityManager in order to enable class downloading. This can be done by adding the following to your code. (It needs to be executed before RMI can download code from remote hosts, so it most likely needs to appear in the main method of your application as can better be perceived from the below illustrations.
Illustration 1:
// Protected synchronized method
protected static synchronized void setSecurityManager() 
{
    if (System.getSecurityManager() == null) 
    {
        // Setting the RMISecurityManager on System
        System.setSecurityManager(new RMISecurityManager());
    }
}
Illustration 2:
// Synchronized method
synchronized static void ensureSecurityManager() 
{
    if (System.getSecurityManager() == null) 
    {
        // Setting the RMISecurityManager on System
        System.setSecurityManager(new RMISecurityManager());
    }
}
Illustration 3:  
// Protected synchronized method
protected static synchronized void setSecurityManager() 
{
    if (System.getSecurityManager() == null) 
    {
        // Setting the RMISecurityManager on System
        System.setSecurityManager(new RMISecurityManager());
    }
}
Example
Java
// Java Program to Illustrate RMISecurityManager Class// Via creating Registry and Rebinding Service  // Importing required classesimport java.lang.Object;import java.lang.SecurityManager;import java.rmi.RMISecurityManager;  // Main classclass GFG {      // Main driver method    public static void main(String[] args)    {          // Try block to check for exceptions        try {              // Setting the RMISecurityManager on System            System.setSecurityManager(                new RMISecurityManager());            RmiService service = new RmiServiceImpl();              // First we will be creating registry            // using createRegistry() method            LocateRegistry.createRegistry(6600);              // Now rebinding the service            // using rebind method            Naming.rebind(                "rmi://127.0.0.1:6600/PersonService",                service);              // Display message on the console for            // successful execution of the program            System.out.println("Service Start!");        }          // Catch block to handle exceptions        catch (Exception e) {              // Printing the line number where exception            // occured using printStackTrace() method            e.printStackTrace();        }    }}
Output: 
Service Start!
On console, we will land up to a display message as shown above.
Java-Classes
Picked
Java
Java
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Stream In Java
Constructors in Java
Exceptions in Java
Functional Interfaces in Java
Different ways of Reading a text file in Java
Generics in Java
Introduction to Java
Comparator Interface in Java with Examples
Internal Working of HashMap in Java
Strings in Java