jpeg decoding when data is given in array

i am using LibJpeg library for decoding jpeg image ( given in form of byte array ) into rgb color map . but it come different from my sample output i want to check by java programme . how to do this in by java programme ? w开发者_Go百科hat is use of APPn in header ? how to decode jpeg image into rgb pixel .

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Why not use ImageIO.read together with ByteArrayInputStream to read the byte array into an image then no extra library is needed (pure java solution):

BufferedImage image = ImageIO.read(new ByteArrayInputStream(bytes));