Fast way to write and read buffered data

[Adam Kronicki]

I have a working implementation of the AudioRecrod class. I however I
need the samples only in a buffered form so I don't want to save them
on the phone hard memory, but keep them in a buffered way. Write now I
am saving the files using an ArrayList of type <Short> like that:

for (int idxBuffer = 0; idxBuffer < bufferRead; ++idxBuffer) {
buffer.add(tempBuffer[idxBuffer]);

}

However you can tell that ArrayList is not an effective way to do
this, and also the values are saved as Short not short. I was thinking
about using some of the stream buffers but they mostly only work with
byte[] arrays not short[]. yes I can convert the short to byte but
that again takes some more time...

What would be the fastest way to do it? Every source I googled seems
to be using the 'save to file' approach which definitely can't be the
fastest way. What would you suggest?