title: Need a fast alternative to Java TreeMap<Integer, Character> that can hold many mappings without slowdown
body: <p>I am writing a Java program that uses a TreeMap and the performance slows down to a crawl once there are 10's of thousands of integer, character mappings.</p>
  
  <p>I was wondering if there is an implementation of some type of sorted set implementation out there that can use the int and char primitives and has something like the "headMap" and "tailMap" functions.</p>
  
  <p>I am looking at Trove currently.  I also looked at an implementation of a linked list that uses an insertion sort but didn't include the head and tail functions.  I think a linked list with an insertion sort would be slower than a tree, though, wouldn't it?</p>