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Java SecurityManager checkExec() method with example

SecurityManager Class checkExec() method: Here, we are going to learn about the checkExec() method of SecurityManager Class with its syntax and example.
Submitted by Preeti Jain, on December 15, 2019

SecurityManager Class checkExec() method

• checkExec() method is available in java.lang package.
• checkExec() method calls checkPermission with FilePermission(commands,"execute") when the given argument holds an absolute path else it calls checkPermission with FilePermission("<<ALL FILES>>","execute").
• checkExec() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• checkExec() method may throw an exception at the time of creating process.
  • SecurityException – This exception may throw when the calling thread is not allowed to create a subprocess and it is called for the current security manager by using exec() method of Runtime.
  • NullPointerException – This exception may throw when the given parameter is null.

Syntax:

    public void checkExec(String commands);

Parameter(s):

• String commands – represents the system-specific commands.

Return value:

The return type of this method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void checkExec(String commands)
// method of SecurityManager 

public class CheckExec {
    public static void main(String[] args) {
        // By using setProperty() method is to set the policy property 
        // with security manager
        System.setProperty("java.security.policy", "file:/C:/java.policy");

        // Instantiating a SecurityManager object
        SecurityManager smgr = new SecurityManager();

        // By using setSecurityManager() method is to set the
        // security manager
        System.setSecurityManager(smgr);

        // By using checkExec(String commands) method is to check 
        //that the given command is executable or not
        smgr.checkExec("TextPad.exe");

        // Display the message when command is executed
        System.out.println("Command Executed..");
    }
}

Output

Exception in thread "main" java.security.AccessControlException: access denied ("java.io.FilePermission" "<<ALL FILES>>" "execute")
	at java.base/java.security.AccessControlContext.checkPermission(AccessControlContext.java:472)
	at java.base/java.security.AccessController.checkPermission(AccessController.java:897)
	at java.base/java.lang.SecurityManager.checkPermission(SecurityManager.java:322)
	at java.base/java.lang.SecurityManager.checkExec(SecurityManager.java:572)
	at CheckExec.main(CheckExec.java:20)