classlib/modules/awt/src/main/native/jpegdecoder/shared/readme.txt

To build JPEG decoder download and then unpack to this directory 
IJG source code using the following link: 

http://www.ijg.org/files/jpegsrc.v6b.tar.gz

IJG source files should be located then in the following directory:
.../gl/JPEGDecoder/jpeg-6b/