## Programmatically Writing a Jar file

The org.eclipse.ui.jarpackager package provides utility classes to programmatically export files to a Jar file. Below is a code snippet that outlines the use of the JarPackageData class:

        void createJar(IType mainType, IFile[] filestoExport) {
            Shell parentShell= ...;
            JarPackageData description= new JarPackageData();
            IPath location= new Path("C:/tmp/myjar.jar");
            description.setJarLocation(location);
            description.setSaveManifest(true);
            description.setManifestMainClass(mainType);
            description.setElements(filestoExport);
            IJarExportRunnable runnable= description.createJarExportRunnable(parentShell);
            try {
                new ProgressMonitorDialog(parentShell).run(true,true, runnable);
            } catch (InvocationTargetException e) {
                // An error has occurred while executing the operation
            } catch (InterruptedException e) {
                // operation has been canceled.
            }
        }

Additional API is provided to create a plug-in specific subclass of JarPackageData. This allows other plug-ins to implement their own Jar export/import wizards and to save the content of the JarPackageData object to a corresponding Jar description file.

Once the JAR is described by a JarPackageData, it can be programmatically written using a JarWriter3.