src/main/java/com/feedzai/fos/impl/weka/utils/pmml/PMMLConsumers.java
private static boolean isGzipped(File file) throws IOException {
        FileInputStream fileInputStream = new FileInputStream(file);

        int head = (fileInputStream.read() & 0xff) | ((fileInputStream.read() << 8 ) & 0xff00 );

        return GZIPInputStream.GZIP_MAGIC == head;
    }
private static boolean isGzipped(File file) throws IOException {
        FileInputStream fileInputStream = new FileInputStream(file);

        int head = (fileInputStream.read() & 0xff) | ((fileInputStream.read() << 8 ) & 0xff00 );

        return GZIPInputStream.GZIP_MAGIC == head;
    }
Checks if the given file is in GZIP format.
<p/>
It checks this by checking the head for the {@link java.util.zip.GZIPInputStream#GZIP_MAGIC} number.

@param file The file to check.
@return {@code true} if the file is in GZIP format, or {@code false}
@throws IOException