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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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Convert Datetime column from UTC to local time in select statement
I'm doing a few SQL select queries and would like to convert my UTC datetime column into local time to be displayed as local time in my query results. Note, I am NOT looking to do this conversion via code but rather when I am doing manual and random SQL queries against my databases.
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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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C# DLL config file
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It is not trivial to create a .NET configuration file for a .DLL, and for good reason. The .NET configuration mechanism has a lot of features built into it to facilitate easy upgrading/updating of the app, and to protect installed apps from trampling each others configuration files.
There...
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...
Compiler Ambiguous invocation error - anonymous method and method group with Func or Action
...roup to a compatible delegate type
(emphasis added) is deeply misleading and unfortunate. I'll have a talk with Mads about getting the word "compatible" removed here.
The reason this is misleading and unfortunate is because it looks like this is calling out to section 15.2, "Delegate compatibi...
Why is there huge performance hit in 2048x2048 versus 2047x2047 array multiplication?
...L is always power of 2.
The six comes from fact that 2^6 == 64 bytes is standard size of cache line.
Now what does this mean? Well it means that if I have address X and address Y and
(X >> 6) - (Y >> 6) is divisible by L (i.e. some large power of 2), they will be stored in the same ca...
Adb Devices can't find my phone [closed]
...ying to get adb to see my Samsung Fascinate phone so that I can install my Android apps via usb to the phone. I am using osx 10.6.7.
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Combining node.js and Python
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For communication between node.js and Python server, I would use Unix sockets if both processes run on the same server and TCP/IP sockets otherwise. For marshaling protocol I would take JSON or protocol buffer. If threaded Python shows up to be a bottleneck, ...
Step-by-step debugging with IPython
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You can use IPython's %pdb magic. Just call %pdb in IPython and when an error occurs, you're automatically dropped to ipdb. While you don't have the stepping immediately, you're in ipdb afterwards.
This makes debugging individual functions easy, as you can just load a file with %load...