question: public static boolean isInputStreamGZIPCompressed ( final PushbackInputStream inputStream ) throws IOException { if ( inputStream == null ) return false ; byte [ ] signature = new byte [ 2 ] ; int readStatus = inputStream . read ( signature ) ; inputStream . unread ( signature ) ; int streamHeader = ( ( int ) signature [ 0 ] & 0xff ) | ( ( signature [ 1 ] << 8 ) & 0xff00 ) ; return readStatus == 2 && GZIPInputStream . GZIP_MAGIC == streamHeader ; }
target:  Checks the InputStream if it contains  GZIP compressed data