Why is a ConcurrentModificationException thrown and how to debug it

Question

I am using a Collection (a HashMap used indirectly by the JPA, it so happens), but apparently randomly the code throws a ConcurrentModificati

Answer 1

Note that the selected answer cannot be applied to your context directly before some modification, if you are trying to remove some entries from the map while iterating the map just like me.

I just give my working example here for newbies to save their time:

HashMap map=new HashMap();
//adding some entries to the map
...
int threshold;
//initialize the threshold
...
Iterator it=map.entrySet().iterator();
while(it.hasNext()){
    Map.Entry item=(Map.Entry)it.next();
    //it.remove() will delete the item from the map
    if((Integer)item.getValue()