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What is a NullPointerException, and how do I fix it?
...m = new Integer(10);
The first line declares a variable named num, but it does not actually contain a primitive value yet. Instead, it contains a pointer (because the type is Integer which is a reference type). Since you have not yet said what to point to, Java sets it to null, which means "I am po...
Handling the window closing event with WPF / MVVM Light Toolkit
...ew. Even when the event is bound in code-behind of the View, the ViewModel does not depend on the View and the closing logic can be unit-tested.
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Else clause on Python while statement
...the code, and made it more clear how this answers the question (because it does answer part of it).
– Mark
Dec 3 '14 at 12:52
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preferredStatusBarStyle isn't called
...
setting the rootviewcontroller does not change anything. You should work with the comment of Jon. And be careful when calling setneedsstatusbarappearanceUpdate. You should call it from the parent to work.
– doozMen
Au...
What is the proper REST response code for a valid request but an empty data?
...you successfully fetched. Not appropriate when the entity you're fetching doesn't exist.
202 is used when the server has begun work on an object but the object isn't fully ready yet. Certainly not the case here. You haven't begun, nor will you begin, construction of user 9 in response to a GET re...
What's the difference between Git Revert, Checkout and Reset?
...en remotely similar.
git revert
This command creates a new commit that undoes the changes from a previous commit. This command adds new history to the project (it doesn't modify existing history).
git checkout
This command checks-out content from the repository and puts it in your work tree. It ...
When should I use a struct rather than a class in C#?
...dition, realize that when a struct implements an interface - as Enumerator does - and is cast to that implemented type, the struct becomes a reference type and is moved to the heap. Internal to the Dictionary class, Enumerator is still a value type. However, as soon as a method calls GetEnumerator()...
Domain Driven Design: Domain Service, Application Service
...rastructure Services.
Domain Services : Encapsulates
business logic that doesn't naturally
fit within a domain object, and are NOT typical CRUD operations – those would belong to a Repository.
Application Services : Used by
external consumers to talk to your
system (think Web Services). If cons...
How to “perfectly” override a dict?
... have a simple dict in which the keys are lowercase.
The accepted answer doesn't actually subclass dict, and a test for this fails:
>>> isinstance(MyTransformedDict([('Test', 'test')]), dict)
False
Ideally, any type-checking code would be testing for the interface we expect, or an abst...
Pointers, smart pointers or shared pointers? [duplicate]
...ll as releasing the pointer, allowing someone else to own it. Copying them does not make sense.
Shared pointers is a stack-allocated object that wraps a pointer so that you don't have to know who owns it. When the last shared pointer for an object in memory is destructed, the wrapped pointer will al...