How can I find out, which jar-files java is currently running (and their PIDs)?
I have a .jar file which is notorious for malfunctions. When a malfunction occurs, only a restart helps. I have a way to detect that malfunctions (reading the log-file of said .jar) So I want to write a script, that kills the process whenever the malfunction occurs. The problem is:
confus@confusion:~$ ps -A
...
4438 ? 00:00:00 java
4439 ? 00:00:00 java
4443 ? 00:00:00 java
...
The process name of all running .jars is naturally "java". How do I find out, which of these "java"-processes is the one I want to kill, i.e. the one running foobar.jar?
Solution 1:
You can run the lsof command, which lists which processes has open files, with your jar file given as an argument. An example viewing a file with less:
egil@mutter:~$ lsof foo.c
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
less 18871 egil 4r REG 8,2 0 53862540 foo.c
egil@mutter:~$
To easily reuse the pid in a script, you could run it in terse mode:
egil@mutter:~$ lsof -t foo.c
18871
Or use it with the pids of the several java processes:
$ lsof -p 4438
Solution 2:
Using ps ax will help.
It will display the process tree in a BSD style which simply shows way more information.
To find your particular process you just have to grep for the JAR name. ps ax | grep JARNAME will do it.
Solution 3:
You can do this native or if "lsof" is not installed via /proc//fd Example:
ps -ef|grep -w java
...
0c4 6917 6916 0 12:22 pts/7 00:00:00 java
...
ls -la /proc/6917/fd/
total 0
dr-x------ 2 0c4 svauser 0 Apr 2 12:23 .
dr-xr-xr-x 9 0c4 svauser 0 Apr 2 12:22 ..
lrwx------ 1 0c4 svauser 64 Apr 2 12:23 0 -> /dev/pts/7
lrwx------ 1 0c4 svauser 64 Apr 2 12:23 1 -> /dev/pts/7
lrwx------ 1 0c4 svauser 64 Apr 2 12:23 2 -> /dev/pts/7
lr-x------ 1 0c4 svauser 64 Apr 2 12:23 3 -> /opt/jdk1.8.0_191/jre/lib/rt.jar
lr-x------ 1 0c4 svauser 64 Apr 2 12:23 4 -> /media/veracrypt1/Downloads/rr/testone.jar
lr-x------ 1 0c4 svauser 64 Apr 2 12:23 5 -> /usr/share/java/gnu-getopt-1.0.14.jar