The Java NIO package offers the possibility to transfer bytes between two Channels without buffering them into the application memory.. To read the file from our URL, we'll create a new ReadableByteChannel from the URL stream:. ReadableByteChannel readableByteChannel = Channels.newChannel(url.openStream()); The bytes read from the ReadableByteChannel will be transferred to a FileChannel Here, you can open the PDF files present in your mobile device. This is the most used approach for opening the PDF in an Android device. From the Internet: Here, you can open PDF files from the internet. All you need to do is just use the URL of the PDF file and after downloading the PDF file, you can open the PDF file in your mobile application.