protected File extractDirectory(String dirName) {
protected synchronized File extractDirectory(String dirName) {
	protected File extractDirectory(String dirName) {		if (!checkedOpen())			return null;		Enumeration entries = zipFile.entries();		while (entries.hasMoreElements()) {			String entryPath = ((ZipEntry) entries.nextElement()).getName();			if (entryPath.startsWith(dirName) && !entryPath.endsWith("/")) //$NON-NLS-1$				getFile(entryPath, false);		}		return getExtractFile(dirName);	}