Automatic adjusting of the volum level

Question

Does anybody know in witch way/how the player does the automatic adjusting of the volum level? How does the automatic adjusting of the volum level work? Is it just the decibel that is "normalising"? How does the player measure it? Are the frequenses exactly the same in a song/tune after the automatic adjusting?
Is there anything else in the sound that is influenced in any way?
JN
Macbook Pro   Mac OS X (10.4.8)  

Answer 1

Again, camickr is great, and, clever.
Here's the working code basing on his suggestion.
It is my first time for calling prepareRenderer() from within application code.
I have had overridden it many times in the past, though.
    width = 0;
    cc = table.getColumnCount();
    rc = table.getRowCount();
    for (int c = 0; c < cc; ++c){
      maxcw = 0;
      for (int r = 0; r < rc; ++r){
        Component compo
         = table.prepareRenderer(table.getCellRenderer(r, c), r, c);
        int w = compo.getPreferredSize().width;
        if (w > maxcw){
          maxcw = w;
      maxcw += 7; // somehow, this handcraft is necessary
      table.getColumn(table.getColumnName(c)).setPreferredWidth(maxcw);
      width += maxcw;
    height = (table.getRowCount() + 1) * table.getRowHeight(); // +1 == header
    js.setPreferredSize(new Dimension(width, height));
    // js is a JScrollPane enclosing the table