List of Java processes

Question

How can I list all Java processes in bash? I need an command line. I know there is command ps but I don't know what parameters I need to use.

Answer 1

There's a lot of ways of doing this. You can use java.lang.ProcessBuilder and "pgrep" to get the process id (PID) with something like: pgrep -fl java | awk {'print $1'}. Or, if you are running under Linux, you can query the /proc directory.

I know, this seems horrible, and non portable, and even poorly implemented, I agree. But because Java actually runs in a VM, for some absurd reason that I can't really figure out after more then 15 years working the JDK, is why it isn't possible to see things outside the JVM space, it's really ridiculous with you think about it. You can do everything else, even fork and join child processes (those were an horrible way of multitasking when the world didn't know about threads or pthreads, what a hell! what's going in on with Java?! :).

This will give an immense discussion I know, but anyways, there's a very good API that I already used in my projects and it's stable enough (it's OSS so you still need to stress test every version you use before really trusting the API): https://github.com/jezhumble/javasysmon

JavaDoc: http://jezhumble.github.io/javasysmon/, search for the class com.jezhumble.javasysmon.OsProcess, she will do the trick. Hope it helped, best of luck.

Answer 2

jps -lV

is most useful. Prints just pid and qualified main class name:

2472 com.intellij.idea.Main
11111 sun.tools.jps.Jps
9030 play.server.Server
2752 org.jetbrains.idea.maven.server.RemoteMavenServer

Answer 3

pgrep -l java
ps -ef | grep java

Answer 4

ps axuwww | grep java | grep -v grep

The above will

• show you all processes with long lines (arg: www)
• filter (grep) only lines what contain the word java, and
• filter out the line "grep java" :)

(btw, this example is not the effective one, but simple to remember) ;)

you can pipe the above to another commands, for example:

ps axuwww | grep java | grep -v grep | sed '.....'  | while read something
do
    something_another $something
done

etc...