Re: dsdds

When manipulating an indexed sequence of data elements (e.g. some bytes
in an array of bytes), one often wants to designate a chunk within that
sequence (e.g. when sending part of a byte[] into a stream). The Java
standard library mainly uses two API conventions for designating such
a chunk:

1. offset and length
   The chunk is described by the index of its first element (the offset)
   and the number of consecutive elements the chunk consists in.
   Examples:
      OutputStream.write(byte[] b, int offset, int length)
      ByteBuffer.get(byte[] dst, int offset, int length)
      Writer.write(char[] cbuf, int off, int len)
      String.copyValueOf(char[] data, int offset, int count)

2. begin and end index
   The chunk is described by the index of its first element, and the
   index of the element which immediately follows the chunk.
   Examples:
      Arrays.copyOfRange(byte[] orig, int from, int to)
      String.substring(int beginIndex, int endIndex)
      List.subList(int fromIndex, int toIndex)

The two conventions are mostly equivalent (going from one to another is
a matter of a simple addition or subtraction) but the presence of both
tends to be, at times, a bit confusing. Is there any known design rule
which Sun follows to decide which convention to use ?