Java: Synchronizing on primitives?

Question

In our system, we have a method that will do some work when it\'s called with a certain ID:

public void doWork(long id) { /* ... */ }

Now, this

Answer 1

Wouldn't it be enough to use a SynchronizedHashMap or Collections.synchronizedMap(Map m) from the java.util.concurrent package instead of a plain HashMap where calls for retrieving and inserting are not synchronized?

something like:

Map myMap = new HashMap();
Map mySyncedMap=Collections.synchronizedMap(myMap);