SecurityManager checkConnect(String, int, Object) in Java

checkConnect(String, int, Object): This method is available in the java.lang.SecurityManager class of Java.

Syntax:

void java.lang.SecurityManager.checkConnect(String host, int port, Object context)

This method takes three arguments. This method 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.

Parameters: Three parameters are required for this method.

host: the host name port to connect to.

port: the protocol port to onnect to.

context: a system-dependent security context.

Returns: NA

Throws:

1. SecurityException - if the specified security context is not an instance of AccessControlContext(e.g., is null), or does not have permission to open a socket connection to the specified host and port.

2. NullPointerException - if the host argument is null.

Approach 1: SecurityException 

Java

package com.SecurityManager;

public class SecurityManagercheckConnect2 {
    public static void main(String[] args) {

        SecurityManager securityManager = new SecurityManager();

        String host = "www.google.com";
        Object context = "hello";
        securityManager.checkConnect(host, 0, context);
        System.out.println("Successfully check the access");
    }
}

Output:

Exception in thread "main" java.lang.SecurityException
	at java.base/java.lang.SecurityManager.checkPermission(SecurityManager.java:446)
	at java.base/java.lang.SecurityManager.checkConnect(SecurityManager.java:966)
	at com.SecurityManager.SecurityManagercheckConnect2.main(SecurityManagercheckConnect2.java:10)

Approach 2: NullPointerException

Java

package com.SecurityManager;

public class SecurityManagercheckConnect2 {
    public static void main(String[] args) {

        SecurityManager securityManager = new SecurityManager();

        String host = null;
        Object context = "hello";
        securityManager.checkConnect(host, 0, context);
        System.out.println("Successfully check the access");
    }
}

Output:

Exception in thread "main" java.lang.NullPointerException: host can't be null
	at java.base/java.lang.SecurityManager.checkConnect(SecurityManager.java:956)
	at com.SecurityManager.SecurityManagercheckConnect2.main(SecurityManagercheckConnect2.java:10)

Some other methods of SecurityManager

SecurityManager(): This method constructs a new SecurityManager.

checkAccept(String, int): This method throws a SecurityException if the calling thread is not permitted to accept a socket connection from the specified host and port number.

checkAccess(Thread): This method throws a SecurityException if the calling thread is not allowed to modify the thread argument.

checkAccess(ThreadGroup): This method throws a SecurityException if the calling thread is not allowed to modify the thread group argument.

checkConnect(String, int): This method throws a SecurityException if the calling thread is not allowed to open a socket connection to the specified host and port number.

checkConnect(String, int, Object): This method throws a SecurityException if the specified security context is not allowed to open a socket connection to the specified host and port number.

checkCreateClassLoader(): This method throws a SecurityException if the calling thread is not allowed to create a new class loader.

checkDelete(String): This method throws a SecurityException if the calling thread is not allowed to delete the specified file.

checkExec(String): This method throws a SecurityException if the calling thread is not allowed to create a subprocess.

checkExit(int): This method throws a SecurityException if the calling thread is not allowed to cause the Java Virtual Machine to halt with the specified status code.

checkLink(String): This method throws a SecurityException if the calling thread is not allowed to dynamic link the library code specified by the string argument file.

checkListen(int): This method throws a SecurityException if the calling thread is not allowed to wait for a connection request on the specified local port number.

checkMulticast(InetAddress): This method throws a SecurityException if the calling thread is not allowed to use(join/leave/send/receive) IP multicast.

checkPackageAccess(String): This method throws a SecurityException if the calling thread is not allowed to access the specified package.

checkPackageDefinition(String): This method throws a SecurityException if the calling thread is not allowed to define classes in the specified package.

checkPermission(Permission): This method throws a SecurityException if the requested access, specified by the given permission, is not permitted based on the security policy currently in effect.

checkPermission(Permission, Object): This method throws a SecurityException if the specified security context is denied access to the resource specified by the given permission.

checkPrintJobAccess(): This method throws a SecurityException if the calling thread is not allowed to initiate a print job request.

checkPropertiesAccess(): This method throws a SecurityException if the calling thread is not allowed to access or modify the system properties.

checkPropertyAccess(String): This method throws a SecurityException if the calling thread is not allowed to access the system property with the specified key name.

checkRead(FileDescriptor): This method throws a SecurityException if the calling thread is not allowed to read from the specified file descriptor.

checkRead(String): This method throws a SecurityException if the calling thread is not allowed to read the file specified by the string argument.

checkRead(String, Object): This method throws a SecurityException if the specified security context is not allowed to read the file specified by the string argument.

checkSecurityAccess(String): This method determines whether permission with the specified target name should be granted or denied.

checkSetFactory(): This method 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.

checkWrite(FileDescriptor):  This method throws a SecurityException if the calling thread is not allowed to write to the specified file descriptor.

checkWrite(String): This method throws a SecurityException if the calling thread is not allowed to write to the file specified by the string argument.

getSecurityContext(): This method creates an object that encapsulates the current execution environment.

getThreadGroup(): This method returns the thread group into which to instantiate any new thread being created at the time this is being called.