private RepositoryDescriptor getContentJarDescriptor(File jarFile) {
		InputStream contentsFileInputStream = null;
		ZipFile zipFile = null;
		try {
			zipFile = new ZipFile(jarFile);
			ZipEntry entry = zipFile.getEntry("content.xml");
			if (entry != null) {
				logger.debug(Messages.RESOLVED_JAR_FILE.value(entry.getName()));
				contentsFileInputStream = zipFile.getInputStream(entry);
				return UpdateSiteDescriptorReader.read(contentsFileInputStream, logger);
			} else {
				logger.warn(Messages.DESCRIPTOR_NOT_RESOLVED.value());
			}
		} catch (IOException e) {
			logger.warn(e.getMessage(), e);
		} catch (JDOMException e) {
			logger.warn(e.getMessage(), e);
		} finally {
			if (contentsFileInputStream != null) {
				try {
					contentsFileInputStream.close();
				} catch (IOException e) {
					logger.warn(e.getMessage(), e);
				}
			}
			if (zipFile != null) {
				try {
					zipFile.close();
				} catch (IOException e) {
					logger.warn(e.getMessage(), e);
				}
			}
		}
		return null;
	}