title: Concat two populated arraylists without overwriting anything?
body: <p>I have an arraylist which is populated (call this A). I have another arraylist, which is also populated (call this B).</p>
  
  <p>A has 5 elements
  B has 3 elements</p>
  
  <p>Is it possible for me to add all of B's elements to A, so that B's elements start from 6 (length of A + 1), with a total of 8 elements. I am hoping to do this witout any elaborate loops but a built in method?</p>
  
  <p>Also, performance wise, how bad is this sort of idea (if it is bad at all)?</p>
  
  <p>Thanks</p>