This web site contains a number of links to Java programs that were
covered in lectures. These links are typically labelled with the
suffix jar
. On this web page, I explain how to
take copies of these files.
- Download: Do not use your left mouse button to
follow the hyperlink! If you do, the page that appears will contain
quantities of apparent gobbledegook. Cutting-and-pasting this
gobbledegook into another file is a completely pointless thing to do.
This will not work!
Instead…
Click on the hyperlink using your mouse's right button. A menu should appear and one of the options on the menu will be
Save
. Use this to save the file in some suitable part of your home directory. - Unpack: The file you have saved may contain
several other files. They were concatenated together and compressed
using a Java tool called
jar
. To extract the files, we again usejar
.Suppose the file is called
agentDemonstrator.jar
. To extract its contents, type the following:jar xf agentDemonstrator.jar
If you now list your current directory, you should find new files or directories. In this example, you'll find a new directory called
agentDemonstrator
. The Java program is in this subdirectory.There are many more sophisticated things you can do with
jar
. If you want to know about them, consult our local copy of the Java tools reference page. - Tidy up: You can save disk space and keep your
directories tidy by deleting two things: the
jar
file (e.g.agentDemonstrator.jar
) and another directory that gets created calledMETA-INF
.