You can read data from a PDF file using the read() method of the FileInputStream class this method requires a byte array as a parameter.
import java.io.File; import java.io.FileInputStream; import java.io.ByteArrayOutputStream; public class PdfToByteArray { public static void main(String args[]) throws Exception { File file = new File("sample.pdf"); FileInputStream fis = new FileInputStream(file); byte [] data = new byte[(int)file.length()]; fis.read(data); ByteArrayOutputStream bos = new ByteArrayOutputStream(); data = bos.toByteArray(); } }