I am trying to execute chmod command from Java in a running Docker container:

String cmd = "docker exec -it " + POSTGRES_CONTAINER_NAME + " bash -c 'chmod +x /tmp/dump.sh'";

  Runtime rt = Runtime.getRuntime();
  Process pr = rt.exec(cmd);

  BufferedReader br = new BufferedReader(new InputStreamReader(pr.getInputStream()));
  for (String line = br.readLine(); line != null; line = br.readLine()) {
    LOGGER.debug("L:{}", line);
  }

There is a problem because execution flag is not set (and I am not getting any message from docker exec).

docker exec -it postgres_intm bash -c "ls -la /tmp/dump.sh"
-rw-r--r-- 1 root root 134 Jun  4 20:59 /tmp/dump.sh

When I call a chmod from command line manually, an execution permission is set correctly:

docker exec -it postgres_intm bash -c 'chmod +x /tmp/dump.sh'

docker exec -it postgres_intm bash -c "ls -la /tmp/dump.sh"  
-rwxr-xr-x 1 root root 134 Jun  4 20:59 /tmp/dump.sh

Q: What am I doing wrong that Java code doesn’t set a execution permission?