check UID with Java

Hi All,

I have to make a java program which checks first if the user running the program in UNIX is root or not. I know the command id -u but I don't know how to implement it in the Java program. Any help would be appreciated.

You could run the native program with java.lang.Runtime.exec() or you could check the current user name with java.lang.System.getProperty().

I think it should be the other way round - you should write a shell script that checks this, and only if the user is root would you call a Java app.

There's no way to check for a root user in native Java, since the concept is OS-dependent and therefore excluded under the "write-once/run-anywhere rule". The easiest way to check is to do a Runtime.exec on the "id -u" or "id -g" command. You'll have to capture and parse the number passed back on stdout.

I know this is an old post, but I just responded to this same question on StackOverflow and thought it would be helpful to post here as well.

On the Linux systems that I work with, you can get the user's UID with this:var uidStr = Files.readString(Paths.get("/proc/self/loginuid"));Note that this is the user id associated with the username used to log-in, not effective user id.