Creating a jar File in Eclipse
This page shows you how to create a jar file (java archive)
using the Eclipse IDE. The instructions are for bundling the source code (.java
files) into a jar. These instructions do not cover how to make an executable
the instructions from the Eclipse documentation.
To create a new JAR file in the workbench:
- Either from the context menu or from the menu bar's File
menu, select Export.
- Expand the Java node and select JAR file.
- In the JAR File Specification page, select the resources
that you want to export in the Select the resources to export field.
- Select the appropriate checkbox to specify whether you want to
Export generated class files and resources or Export Java
source files and resources. (Note: Selected
resources are exported in both cases.
IMPORTANT: In this example the project keeps the source code in a
folder named src. Your project may have a different set up. Be sure you expand
the tree to show the default package and that the .java files are checked on
the right. Alternatively deselect the option that says Export generated
class files and resources and select the option that says Export Java
source files and resources. For CS307 we want the .java files. We do not want
or need the .class files. If you do not turn in your source files, the .java
files, your assignment grade will be 0.
If there are other files or resources you want to include they must be in a an
open project. Browse to their location via the directory tree on the left and
ensure the file or resource is checked in the window on the right. In the
example below we are including a file named OtherFile.txt which
is located in the A3 directory.
- In the Select the export destination field, either type
or click Browse to select a location for the JAR file.
- Select or clear the Compress the contents of the JAR file
checkbox. (This option is unimportant for CS307.)
- Select or clear the Overwrite existing files without warning
checkbox. If you clear this checkbox, then you will be prompted to confirm the
replacement of each file that will be overwritten. (This option is unimportant
- You have two options:
- Now, navigate to the location you specified for the jar. The icon you see
and the behavior you get if you double click it will vary depending on how
your computer is set up.
One easy way of checking if the jar has the correct files is to rename it with
a .zip extension. Then use whatever you zip program is to look at the files
inside. (This may not work depending on how your system is set up.)
Rename to .zip extension:
Open up with zip program / utility.
In the above image you can see that A3.jar (renamed to A3.zip) contains 2
files MathMatrix.java and MathMatrixTester.java. Realize you may have multiple
copies of those files on your computer. You can unzip the file (in a location
different from where the files were originally located!!) and open the .java
files to ensure they are correct or compare the size of the files to the size
of the originals. Alternatively you can
unjar the jar file, again in a different location that the original .java
files, and check the files.
If you changed the extension to .zip you must change it back to .jar before
submitting your file via turnin.