Same as Before

The dump of the new file is indistinguishable from that of the previous file. The two shorts, each containing zero, are written out as 32 zero bits. Previously, an int containing zero was written out as 32 zero bits. There is nothing in the file that distinguishes one situation from the other.

A program that reads data from this file must be written with the knowledge of how the file was written. (Since I know how it was written, I put brackets under the bytes to show the intended groupings).

Here is an excerpt from the DataOutputStream DataOutputStream, documentation documentation.

public void writeBytes(String s) throws IOException
    — write the low eight bits of each character of the string.

This does not write the entire String object to the stream. It merely writes bytes from the characters of the String. A String object (like all objects) is a big chunck of memory with its own data, methods, and internal organization.

The writeBytes() method just writes out the characters. If the characters in a String are from the usual Western alphabet, the writeBytes() method writes normal 8-bit ASCII.