weakhashmap

Can the following piece of code be rewritten w/o using Collections.synchronizedMap() yet maintaining correctness at concurrency? Collections.synchronizedMap(new WeakHashMap<Class, Object>()); i.e. is there something from java.util.concurrent one can use instead? Note that merely replacing with new ConcurrentHashMap<Class, Object>(new WeakHashMap<Class, Object>())); obviously won't work Steven Schlansker Guava 's CacheBuilder class allows you to do this easily. CacheBuilder.newBuilder().weakKeys().build() Note that this changes key equality semantics to be == instead of .equals() which will not

This question already has an answer here: When would you use a WeakHashMap or a WeakReference? 10 answers What is a WeakHashMap and when should one be using it? What are the differences between a WeakHashMap and a HashMap ? vickirk Elements in a weak hashmap can be reclaimed by the garbage collector if there are no other strong references to the key object, this makes them useful for caches/lookup storage. Weak reference are not restricted to these hash tables, you can use WeakReference for single objects. They are useful to save resource, you can keep a reference to something but allow it to