Static hashmap not working

问题

I have a multi module maven project. In which I have initialized a static hashmap in a common module. I am inserting values in that hashmap in other module called controller and when I want to iterate that hashmap in third module then it gives null.

Here is my static hashmap initialization:

public static HashMap<String, Integer>   hmSimultaneousRequestTracker = new  HashMap<String, Integer>();

Controller module:
            Constants.hmSimultaneousRequestTracker.put(inputjson.getSettings().getUsername(),1);

Third module:
    for (Map.Entry<String, Integer> entry : Constants.hmSimultaneousRequestTracker.entrySet()) {

            if(entry.getKey().equals(username)){
                if(entry.getValue()>0);
                {
                int value = entry.getValue()-1  ;
                    entry.setValue(value);
                }
            }
        }

In this I get hashmap null.

来源：https://stackoverflow.com/questions/30373115/static-hashmap-not-working