ulimit -n returns different value via java program

Asked Jun 03 '18 at 17:51

Active Jun 04 '18 at 05:00

Viewed 47 times

I ran:

public class RuntimeExecTest {
public static void main(String[] args) throws IOException {

    Process exec = Runtime.getRuntime().exec(new String[]{"bash", "-c", "ulimit -n"});
    BufferedReader in = new BufferedReader(
            new InputStreamReader(exec.getInputStream()));
    String line = null;
    while ((line = in.readLine()) != null) {
        System.out.println(line);
    }
}

}

on linux as java program. This command returned 50000 which is a number open file descriptors stored in my /etc/security/limits.conf and its a hard limit. But whenever I run:

"bash" "-c" "ulimit -n"

from linux terminal I get 30000 which is my soft limit from /etc/security/limits.conf

Why I get hard limit via java program and soft limit via linux terminal?

I think it's not a problem with wrong command construction. Just java program read wrong values but I don't know why

edited Jun 04 '18 at 05:00

asked Jun 03 '18 at 17:51

Michal

Perhaps the Java runtime adjusts the ulimit before executing your user code. Run `strace` to see. – Jonathon Reinhart Jun 03 '18 at 17:55
Do you get the same result by substituting with `"bash", "-c", "ulimit", "-n"` ? – Daniele Jun 03 '18 at 18:00
if i run "bash", "-c", "ulimit", "-n" I get "unlimited" – Michal Jun 03 '18 at 18:04
Can you include a full MCVE including invocation? This helps rule out things like doing this on a server process. – that other guy Jun 03 '18 at 21:21
1

@Turing85 it's not a duplicate of that one, OPs invocation is correct – that other guy Jun 03 '18 at 21:22
I put an exact java code that I run on linux machine – Michał Wolnicki Jun 04 '18 at 08:09

ulimit -n returns different value via java program

0 Answers0