The conventional location for storing my Java libraries and applications in UNIX based systems

I usually store the Java applications and JAR files that I download from the Web in the ~/Java folder on my computer (an OS X machine). I have been doing this since the days when I was a Windows user. However I think in UNIX based systems user local apps are conventionally stored in another directory. I have a feeling that this directory should either be /usr/local/, /usr/local/USERNA开发者_如何学CME, /opt/local, or /opt/local/USERNAME but I am not sure. Any ideas which directory can I use for this purpose?

Please note that, I am talking about archive files that I download from the Web, unpack and use locally and not programs that have installation scripts or MacPorts, etc.

The para-answer is that you shouldn't be downloading jars by hand at all, you should be using Gradle, Ivy, Maven, or something similar to manage your jars for you. These tools take a simple specification of your dependencies as input, and go and find, download, store, and make available all the necessary jar files. This takes a little bit of getting used to, but are rather wonderful once you're in the swing of it.

A direct answer, though, is that on orthodox unix, these files belong in /usr/local/share. usr because they're read-only data that is not part of the base operating system, local because they are not being supplied by the operating system (which owns the rest of /usr), and share because jar files are architecture-independent.

Note that on FreeBSD, the 'ports' package management system puts files in /usr/local, but i believe it shares it with the local administrator. There isn't some other location where purely local files go.

If the system has a convention for where package-managed jars go, then copy that under /usr/local. For example, on Ubuntu, there is /usr/share/java, so you should use /usr/local/share/java.

Further, if the system has a convention for handling versions, copy that. Again, on Ubuntu, jars are all stored in one directory, with version numbers in the name, but with a versionless symlink pointing to the default/latest version. So, i have a file at /usr/share/java/xstream-1.3.1.jar, and a symlink at /usr/share/java/xstream.jar pointing to it. I'd use the same approach in /usr/local/share/java.

Now, that's for orthodox unix. You're on OS X, which is not orthodox unix. Still, the principles apply: find how the system stores jars it provides, and transpose that into a user-managed filesystem space.

There isn't any blessed way to do it. You may, however, run into having multiple versions of a jar, and then it just goes downhill from there.

I usually download the jars I need as a distribution, and unpack it to its own folder, and then add the jars to the projects I need them for in my IDE. For libraries a common approach is to use Maven and its dependency handling.

So, my suggestion is to keep your current way of doing it, if you like that, but have each project in its own folder, like

~/Java/jakarta-commons-net-1.1.8/commons-net.jar

Apple have a note giving /Library/Java/Extensions as the directory for shared jars and ~/Library/Java/Extensions for jars just for yourself. These paths are on the classpath.

The jars can be anywhere as long as that directory is on your class path. (I use a version of Thorbjørn Ravn Andersen's style I use ~/Library/Jar/jakarta-commons-net-1.1.8/commons-net.jar)

See Tom Anderson's answer for a better way to do it using ivy etc

You might wish to read the Filesystem Hierarchy Standard /opt or /usr/local are probably appropriate but you should read there FHS definitions first.

On FreeBSD systems the location is ${LOCALBASE}/share/java -- and subdirectories thereof. Not that all software-ports respect it, but they should.

LOCALBASE is usually /usr/local -- unless overwritten by the system administrator.