To decode / uncompress the received HTTP POST data in PHP code, request data coming from Java / Android application via HTTP POST GZIP / DEFLATE compressed format

1) Data sent from Java Android app to PHP using DeflaterOutputStream java class and received in PHP as shown below
echo gzinflate( substr($HTTP_RAW_POST_DATA,2,-4) ) . PHP_EOL  . PHP_EOL;

2) Data sent from Java Android app to PHP using GZIPOutputStream java class and received in PHP code as shown below
echo gzinflate( substr($HTTP_RAW_POST_DATA,10,-8) ) . PHP_EOL  . PHP_EOL;

From Java Android side (API level 10+), data being sent in DEFLATE compressed format
        String body = "Lorem ipsum shizzle ma nizle";
        URL url = new URL("http://www.url.com/postthisdata.php");
        URLConnection conn = url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestProperty("Content-encoding", "deflate");
        conn.setRequestProperty("Content-type", "application/octet-stream");
        DeflaterOutputStream dos = new DeflaterOutputStream(
                conn.getOutputStream());
        dos.write(body.getBytes());
        dos.flush();
        dos.close();
        BufferedReader in = new BufferedReader(new InputStreamReader(
                conn.getInputStream()));
        String decodedString = "";
        while ((decodedString = in.readLine()) != null) {
            Log.e("dump",decodedString);
        }
        in.close();

On PHP side (v 5.3.1), code for decompressing this DEFLATE data will be
    echo substr($HTTP_RAW_POST_DATA,2,-4);

From Java Android side (API level 10+), data being sent in GZIP compressed format

        String body1 = "Lorem ipsum shizzle ma nizle";
        URL url1 = new URL("http://www.url.com/postthisdata.php");
        URLConnection conn1 = url1.openConnection();
        conn1.setDoOutput(true);
        conn1.setRequestProperty("Content-encoding", "gzip");
        conn1.setRequestProperty("Content-type", "application/octet-stream");
        GZIPOutputStream dos1 = new GZIPOutputStream(conn1.getOutputStream());
        dos1.write(body1.getBytes());
        dos1.flush();
        dos1.close();
        BufferedReader in1 = new BufferedReader(new InputStreamReader(
                conn1.getInputStream()));
        String decodedString1 = "";
        while ((decodedString1 = in1.readLine()) != null) {
            Log.e("dump",decodedString1);
        }
        in1.close();

On PHP side (v 5.3.1), code for decompressing this GZIP data will be
    echo substr($HTTP_RAW_POST_DATA,10,-8);

Useful PHP code for printing out compressed data using all available formats.

$data = "Lorem ipsum shizzle ma nizle";
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzcompress($data,$i))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzdeflate($data,$i))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzencode($data,$i,FORCE_GZIP))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzencode($data,$i,FORCE_DEFLATE))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";

Hope this helps. Please ThumbsUp if this saved you a lot of effort and time.