jodd-core/src/main/java/jodd/io/ZipUtil.java
public static File ungzip(final File file) throws IOException {
		String outFileName = FileNameUtil.removeExtension(file.getAbsolutePath());
		File out = new File(outFileName);
		out.createNewFile();

		FileOutputStream fos = new FileOutputStream(out);
		GZIPInputStream gzis = new GZIPInputStream(new FileInputStream(file));
		try {
			StreamUtil.copy(gzis, fos);
		} finally {
			StreamUtil.close(fos);
			StreamUtil.close(gzis);
		}

		return out;
	}
public static File ungzip(final File file) throws IOException {
		String outFileName = FileNameUtil.removeExtension(file.getAbsolutePath());
		File out = new File(outFileName);
		out.createNewFile();

		FileOutputStream fos = new FileOutputStream(out);
		GZIPInputStream gzis = new GZIPInputStream(new FileInputStream(file));
		try {
			StreamUtil.copy(gzis, fos);
		} finally {
			StreamUtil.close(fos);
			StreamUtil.close(gzis);
		}

		return out;
	}
Decompress gzip archive.