title: Java: Reading and Writing multiple arrays selectively to a single file
body: <p>I know this question have been asked and answered here before, but mine is a special case which I did not find an answer to yet.</p>
  
  <p>I have between 100,000 and a Million arrays of type <code>int</code> with a 'fixed' length of 32^3, I need to store those arrays in a single file without the need to iterate over them.
  I know it is possible with <a href="http://docs.oracle.com/javase/7/docs/api/java/io/ObjectOutputStream.html" rel="nofollow" title="ObjectOutputStream">ObjectOutputStream</a>, I have even found how to write multiple objects to a single file and read them back (which might sound like it solves my problem) but no, it doesn't.</p>
  
  <p>My actual problem is that I need to add/update a single array to that file, and read a single array as well.The whole arrays might have maximum of 10 arrays that were modified in a second, so I will need to write the changes down to that file without the need to rewrite the whole file as this is way to slow and inefficient.</p>
  
  <p>So my question: is it possible to save a fixed length <code>int</code> array to a file containing many <code>int</code> arrays of the same length? and read a specific <code>int</code> array from that file? without having to iterate through each array on reading or writing?</p>