My virus scanner (Sophos) showed that it was scanning a file named rt.jar plus several other .jar files. I was a little bit surprised because I didn't think that Java was installed.

Yet, when I search using Finder, I can't find any indication that this or any other .jar file exists on my system (OSX 10.10).

Any suggestions about where/how to look?

  • Finder doesn't like to search invisible files. You can try force it [with moderate success] or use something like EasyFind (freeware) which is easier to work with
    – Tetsujin
    Apr 29, 2015 at 18:59
  • Can I be confident that EasyFind is safe because it is in the app store?
    – PMichael
    Apr 29, 2015 at 19:05
  • Yes, yes & yes. That's one of the very good things about the App Store; Apple has checked the code for anything that doesn't do what it ought.
    – Tetsujin
    Apr 29, 2015 at 19:08
  • 2
    Thx. Meanwhile, I discovered that the .jar files are in the package that Mathematica installs by using see package contents.
    – PMichael
    Apr 29, 2015 at 19:16

1 Answer 1


The best way to find files is through Terminal. You don't need to download or install any extra applications.

Simply issue the command:

sudo find / -name rt.jar

It will ask your for your password; enter it. Find will go through all of your directories and when it finds any instances of "rt.jar" it will output the directory to your screen. You can then navigate to that directory via finder or through the terminal via the "cd" command

cd /the/path/where/find/located/your/file

you can delete it if you like with the "rm" command

rm rt.jar

If you want to see files in Finder just issue these commands in Terminal:

defaults write com.apple.finder AppleShowAllFiles TRUE; killall Finder

After that, you will be able to search and view all of the hidden files.

If you want to go back to the default view just change the "TRUE" to "FALSE"

defaults write com.apple.finder AppleShowAllFiles FALSE;killall Finder
  • trouble with Terminal is you have to remember what to ask it… really not at all intuitive, without a lot of practise.
    – Tetsujin
    Apr 29, 2015 at 20:10
  • True.. but I am not a fan of "free" utilities - there is always a cost. However, I added a couple command so that you could change the default view so you can use Finder instead. You don't have to issue the second command unless you want to go back to the original way of viewing files.
    – Allan
    Apr 29, 2015 at 21:36
  • I would add -x to the find command to stop it reading network filesystems etc
    – mmmmmm
    Apr 29, 2015 at 21:39

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