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What is the difference between up-casting and down-casting with respect to class variable
... supertype, while downcasting is casting to a subtype. Upcasting is always allowed, but downcasting involves a type check and can throw a ClassCastException.
In your case, a cast from a Dog to an Animal is an upcast, because a Dog is-a Animal. In general, you can upcast whenever there is an is-a re...
How to load local script files as fallback in cases where CDN are blocked/unavailable? [duplicate]
... @Capsule - excellent question. From the docs it looks like you can use callback: function (url, result, key) {...} which fires on load or timeout. The default timeout can be overridden. I can't say I've tried it but looks like it might be worth the awkwardness ;)
– johnhunte...
How to check if an NSDictionary or NSMutableDictionary contains a key?
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Don't you want to use valueForKey, as that would call objectForKey if necessary?
– Raffi Khatchadourian
Dec 21 '11 at 0:39
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Jackson databind enum case insensitive
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In version 2.4.0 you can register a custom serializer for all the Enum types (link to the github issue). Also you can replace the standard Enum deserializer on your own that will be aware about the Enum type. Here is an example:
public class JacksonEnum {
public static enum Da...
Why wasn't PyPy included in standard Python?
...e JIT compilation and lower memory footprint greatly improve the speeds of all Python code?
6 Answers
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How can I style an Android Switch?
...h slider images that let part of the thumb move out of the track was especially helpful as i couldn't work out how they were doing that. (the default slider has the pointy edge bits move past the end of the track to make a square end on one side)
– Glenn.nz
Apr...
How do I check if a column is empty or null in MySQL?
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This will select all rows where some_col is NULL or '' (empty string)
SELECT * FROM table WHERE some_col IS NULL OR some_col = '';
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Count, size, length…too many choices in Ruby?
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In the case where you don't provide a parameter to count it has basically the same effect as calling length. There can be a performance difference though.
We can see from the source code for Array that they do almost exactly the same thing. Here is the C code for the implementation of array.l...
How to generate Class Diagram (UML) on Android Studio (IntelliJ Idea)
... a free plugin that can generate class diagrams with android studio.
It's called SimpleUML.
Update Android Studio 2.2+:
To install the plugin, follow steps in this answer: https://stackoverflow.com/a/36823007/1245894
Older version of Android Studio
On Mac: go to Android Studio -> Preferences -&...
Allow Google Chrome to use XMLHttpRequest to load a URL from a local file
...rying to do a HTTP request using XMLHttpRequest from a local file, it basically fails due to Access-Control-Allow-Origin violation.
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