Adding to the classpath on OSX

Question

Can anyone tell me how to add to the classpath on OSX?

Do you want to fix a single application, a lot of applications for a single user or a lot of application for all users on the machine? — Thorbjørn Ravn Andersen, Nov 04 '09 at 19:10

score 103 · Accepted Answer · answered Nov 04 '09 at 20:03

103

If you want to make a certain set of JAR files (or .class files) available to every Java application on the machine, then your best bet is to add those files to /Library/Java/Extensions.

Or, if you want to do it for every Java application, but only when your Mac OS X account runs them, then use ~/Library/Java/Extensions instead.

EDIT: If you want to do this only for a particular application, as Thorbjørn asked, then you will need to tell us more about how the application is packaged.

answered Nov 04 '09 at 20:03

Matt Solnit

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Saved my day for making JUnit work on Vim with Syntastic syntax checker plugin. I wonder why there wasn't any other simple installation example for this on the www... – Ory Band Dec 17 '12 at 22:09
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Why MAC is not respecting -cp/-classpath options, looks like it always loads the jars from /Library/Java/JavaVirtualMachines – Kanagavelu Sugumar Feb 02 '17 at 18:01
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-jar command is able to scan /Library/Java/Extensions, ~/Library/Java/Extensions – Kanagavelu Sugumar Feb 02 '17 at 18:18
This works great as a workaround, but I agree with @kanagavelu It would be good to know why classpath is being ignored. – JoshOrndorff Sep 15 '17 at 16:55
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I tried placing the jar files in the `Extensions` it does not work – Mrak Vladar Mar 27 '21 at 17:02

score 46 · Answer 2 · answered Jul 03 '12 at 05:14

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In OSX, you can set the classpath from scratch like this:

export CLASSPATH=/path/to/some.jar:/path/to/some/other.jar

Or you can add to the existing classpath like this:

export CLASSPATH=$CLASSPATH:/path/to/some.jar:/path/to/some/other.jar

This is answering your exact question, I'm not saying it's the right or wrong thing to do; I'll leave that for others to comment upon.

answered Jul 03 '12 at 05:14

Andrew Swan

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I just want to add my jar to classpath. Why are there paths to two jars? – cegprakash Feb 19 '15 at 21:11
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He is showing how to add more than 1 jar. He also implies that adding just 1 jar is simply appending `:path/to/jar` to the existing classpath @cegprakash – ylun.ca Jul 09 '15 at 18:32

Bruce Shen · Answer 3 · 2020-11-20T18:52:14.367

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To specify a classpath for a single Java process, you can add a classpath option when you run the Java command.

In you command line. Use java -cp "path/to/your/jar:." main rather than just java main

The option tells Java where to search for libraries.

edited Nov 20 '20 at 18:52

answered Nov 17 '16 at 18:17

Bruce Shen

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score -1 · Answer 4 · edited Nov 19 '13 at 20:15

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If your shell is tcsh or csh, you can set it in /etc/profile. Open terminal, "vim /etc/profile" and add the following line:

setenv CLASSPATH (insert your classpath here)

edited Nov 19 '13 at 20:15

Tim Perry

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answered Nov 04 '09 at 18:42

James Bailey

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score -8 · Answer 5 · edited Jul 04 '14 at 00:55

-8

Normally there's no need for that. First of all

echo $CLASSPATH

If there's something in there, you probably want to check Applications -> Utilites -> Java.

edited Jul 04 '14 at 00:55

Andrew Swan

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answered Nov 04 '09 at 18:43

wishi

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Fixed it for them, to save the dogpiling of downvotes. – Andrew Swan Jul 04 '14 at 00:55
Returns me an empty row? – Koray Tugay Sep 26 '14 at 04:36
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if the CLASSPATH env var is not set in your shell you will get an empty row ... => if you want it to contain something you should set it in .bash_profile , .bashrc or whatever env vars source file your shell might use ... – Yordan Georgiev Oct 19 '17 at 10:19

Adding to the classpath on OSX

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