Question

hi mate i have a global Hashtable in my class, and two thread A and B that work with her.
A reads from HashTable and B write in Hashtable.. is there a problem of mutual exclusion ? i need to syncrhonize it or Hashtable class is safe ?

Answer 1

Hashtable is a thread-safe implementation of the Map interface.

In regular put and get operations you will be safe. However, when you will iterate on it in one thread and modify its contents from another thread, you will have ConcurrentModificationException issues. So, when iterating, make sure you iterate on a copy of the original Hashtable.