Using Symbolic Links in Java

Symbolic links are a useful entity, with which you can introduce some kind of encapsulation. The Symbolic link can be created in a secure environment (ex: DMZ) where users can access with valid credentials.

This helps us to keep the real source safe and the original location hidden. The exposed location, in reality, maybe a virtual path that can be created based on various parameters such as login session, user credentials, etc.

Sample code:

import java.nio.file.*;import java.io.*;public class SymbolicLink{   public static void main(String args[])   {      SymbolicLink symbolicLink = new SymbolicLink();      symbolicLink.proceed();   }      private void proceed()   {      //You can use a secure path here that may be exposed to external users, who may be autorized to perform changes      //The path is referring to restrictedAccess folder and this folder can be provided access so that external users can access      Path symbolicLinkName = Paths.get("/home/sridhar/restrictedAccess/SymLnkForSourceFile");      //This is the source file for which the link is being established      Path soruceName = Paths.get("/home/sridhar/SymbolicLink.java");            try {         Files.createSymbolicLink(symbolicLinkName, soruceName);         System.out.println("SymbolicLink created for " + soruceName);      }catch (IOException ioe) {         System.err.println(ioe);      }   }}/*

Expected output:

Before execution:[[email protected]]# ls -lrt-rw-r--r-- 1 root root 1078 Jun 19 12:41 SymbolicLink.class-rw-r--r-- 1 root root 1274 Jun 19 12:41 SymbolicLink.java

After execution:

[[email protected]]# java SymbolicLinkSymbolicLink created for /home/sridhar/SymbolicLink.java[[email protected]]# ls -lrt-rw-r--r-- 1 root root 1078 Jun 19 12:41 SymbolicLink.class-rw-r--r-- 1 root root 1274 Jun 19 12:41 SymbolicLink.javadrwxr-xr-x 2 root root   33 Jun 19 12:42 restrictedAccess

Executing for a second time results in a exception:

[[email protected]]# java SymbolicLinkjava.nio.file.FileAlreadyExistsException: /home/sridhar/restrictedAccess/SymLnkForSourceFile*/
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