title: Java ArrayList overwrite
body: <p>A simple question: I store some values at an ArrayList at specific positions (indexes). These values are frequently updated by the code. My question is, in order to keep the ArrayList updated, it is sufficient to add the new value at the proper index (i.e. this action overwrites the older value stored there?) or do I have to remove first that value stored in that position of the ArrayList and then add the new value at this (now empty) position in the ArrayList?</p>