In my application, I need to add and remove a filter dynamically.
The problem is, that it occasionally causes NPE because of the subtle bug in
here, this.getFilter() is called twice.
getFilter() is defined in superclass, AbstractFilterable:
private volatile Filter filter;
so, it's volatile, and in my case, when I dynamically remove the filter it becomes null, and in certain cases it happens right between the two calls to getFilter().
The first call to getFilter() returns non-null, so the secand call is performed, which returns null and it causes NPE.
The easy fix for this is not to call getFilter() twice: