title: Java input stream "blocking" and multithreading
body: <p>Can't seem to find anything about input stream "blocking" that describes both what it is and when it occurs. Is this some type of multi-thread prevention of concurrent threads accessing the same stream?</p>
  
  <p>On that note, when two concurrent threads access the same stream at the same time, can this cause problems, or do both threads get their own stream pointers? Obviously, one would need to wait, but hopefully it wouldn't lead to an unchecked exception.</p>