Fixed field-width with no separating whitespace? That's ugly to do in
Java. At least one guaranteed whitespace or any other separator in
between and you could use Scanner. But without a separator you either
need to look for a third-party library, try to make sense out of
DecimalFormat.parse() and accompanying pattern junk, or do some good
old coding, like it follows.

int fieldWidths[] = { 5, 5 };
BuffredReader in = ...

...

String line;
while((line = in.readLine()) != null) {
  int start = 0;
  for(int width: fieldWiths) {
     int end = start + width;
     String field = line.substring(start, end);
     if(field.length() != width) {
        // ups, input to short
     }
     double value = Double.parseDouble(field);
     // do something with the value

     start = end;
  }
}

see http://mindprod.com/jgloss/printf.html