ByteBuffer read-only?

Question

Java

I am learning Java from the book Thinking in Java.
It has this suggestion:

To restrict file access to read -only , explicitly obtain a ByteBuffer using the allocate() static method

The code follows a few pages later. Code snippet:

...
fc = new FileOutputStream("data2.txt").getChannel();
buffer = ByteBuffer.allocate(24);
buffer.asCharBuffer().put("Some text");
fc.write(buffer);
fc.close();
...

What's the use of the allocate() method if I can put "Some text" in the buffer and write its contents to a file?

Answer 1

I suggest reading the documentation and everything will fall into place.

Answer 2

ByteBuffer#asReadOnlyBuffer()