Question

I m new in java.I have a text document with hexadecimal values line by line, i m trying to read it and convert it into byte array. but for the hexadecimal values like 8, d, 11, 0, e4 when parsing i m getting wrong value for e4 as -28 instead of 228.
how can i overcome this conversion error….

          FileInputStream fstream = new FileInputStream("C:/Users/data.txt");

          DataInputStream in = new DataInputStream(fstream);
          BufferedReader br = new BufferedReader(newInputStreamReader(in,"UTF-8"));


          byte[] bytes = new byte[1024];
          String str;
          int i=0;

          while ((str = br.readLine()) != null) 
          {

              bytes[i]= (byte) (Integer.parseInt(str,16) & 0xFF);
              i++;

          }
          byte[] destination = new byte[i];
          System.arraycopy(bytes, 0, destination, 0, i);

          br.close();
          return destination;

Answer 1

As Alnitak said byte is signed in java. Value of 0xe4 = 228 which is unsigned, and the range of byte is -128 to 127.

My suggestion is to use int instead of byte like

int[] bytes = new int[1024];
bytes[i]= Integer.parseInt(str,16);

You get the same thing which you have require.