Bug 37197 Basepath for relative pathes in JAR-exporter
The basepath for the JAR-exporter is the eclipse-install-directory. I prefer it to be the root of the project (the description is saved in), so that relative pathes end inside the project. Now: <jardesc> <jar path="workspace/projectdir/jar.jar"/> Desired: <jardesc> <jar path="jar.jar"/> Reason: To make the jardesc-files portable for shared projects
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarFileExportOperation.java
}
			jProject= je.getJavaProject();
			pkgRoot= JavaModelUtil.getPackageFragmentRoot(je);
		}
		else
			resource= (IResource)element;
		if (!resource.isAccessible()) {
			addWarning(JarPackagerMessages.getFormattedString("JarFileExportOperation.resourceNotFound", resource.getFullPath()), null); 
			return;
		}
		if (resource.getType() == IResource.FILE) {
			if (!resource.isLocal(IResource.DEPTH_ZERO))
				try {
					resource.setLocal(true , IResource.DEPTH_ZERO, progressMonitor);
				} catch (CoreException ex) {
					addWarning(JarPackagerMessages.getFormattedString("JarFileExportOperation.resourceNotLocal", resource.getFullPath()), ex); 
					return;
				}
			if (!isInJavaProject) {
				
				try {
					isInJavaProject= resource.getProject().hasNature(JavaCore.NATURE_ID);
				} catch (CoreException ex) {
					addWarning(JarPackagerMessages.getFormattedString("JarFileExportOperation.projectNatureNotDeterminable", resource.getFullPath()), ex); 
					return;
				}
				if (isInJavaProject) {
					jProject= JavaCore.create(resource.getProject());
					try {
						IPackageFragment pkgFragment= jProject.findPackageFragment(resource.getFullPath().removeLastSegments(1));