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What is a NullPointerException, and how do I fix it?
What are Null Pointer Exceptions ( java.lang.NullPointerException ) and what causes them?
12 Answers
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How to pass json POST data to Web API method as an object?
...s well. The major difference is, In asp.net core, both web api controllers and Mvc controllers are merged together to single controller model. So your return type might be IActionResult or one of it's implementation (Ex :OkObjectResult)
Use
contentType:"application/json"
You need to use JSON....
How to skip over an element in .map()?
...tion would have kept it.
update — This question gets a lot of attention, and I'd like to add the following clarifying remark. The purpose of .map(), as a concept, is to do exactly what "map" means: transform a list of values into another list of values according to certain rules. Just as a paper m...
Getting “type or namespace name could not be found” but everything seems ok?
... when an application is set to target the .Net 4 Client Profile framework, and the project it references targets the full .Net 4 framework.
So to make that clearer:
Project A targets the Client Profile framework
Project A references Project B
Project B targets the full framework
The solution in...
Very large matrices using Python and NumPy
NumPy is an extremely useful library, and from using it I've found that it's capable of handling matrices which are quite large (10000 x 10000) easily, but begins to struggle with anything much larger (trying to create a matrix of 50000 x 50000 fails). Obviously, this is because of the massive memo...
Failed to Attach to Process ID Xcode
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Resetting the content and settings in the simulator worked for me. This is available in the "iOS Simulator" menu.
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Warn user before leaving web page with unsaved changes
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Short, wrong answer:
You can do this by handling the beforeunload event and returning a non-null string:
window.addEventListener("beforeunload", function (e) {
var confirmationMessage = 'It looks like you have been editing something. '
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What is a race condition?
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A race condition occurs when two or more threads can access shared data and they try to change it at the same time. Because the thread scheduling algorithm can swap between threads at any time, you don't know the order in which the threads will attempt to access the shared data. Therefore, the re...
Java HashMap performance optimization / alternative
...or every object:
public int hashCode() {
// assume that both a and b are sorted
return a[0] + powerOf52(a[1], 1) + powerOf52(b[0], 2) + powerOf52(b[1], 3) + powerOf52(b[2], 4);
}
public static int powerOf52(byte b, int power) {
int result = b;
for (int i = 0; i < p...
Canvas is stretched when using CSS but normal with “width” / “height” properties
I have 2 canvases, one uses HTML attributes width and height to size it, the other uses CSS:
8 Answers
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