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What is the concept of erasure in generics in Java?
...al" argument as well? Answer: type erasure. This sort of thing pollutes an API. Out of interest, have you used .NET generics much? (continued)
– Jon Skeet
Dec 29 '09 at 13:18
5
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WebDriver: check if an element exists? [duplicate]
...ust in case anyone needs a pointer to it: selenium.googlecode.com/git/docs/api/java/org/openqa/selenium/…
– Chen Xie
Mar 20 '15 at 22:35
...
What is null in Java?
...e = reader.readLine()) != null) {
process(line);
}
One can design the API so that the termination condition doesn't depend on readLine() returning null, but one can see that this design has the benefit of making things concise. Note that there is no problem with empty lines, because an empty li...
How to listen for changes to a MongoDB collection?
...
Since MongoDB 3.6 there will be a new notifications API called Change Streams which you can use for this. See this blog post for an example. Example from it:
cursor = client.my_db.my_collection.changes([
{'$match': {
'operationType': {'$in': ['insert', 'replace']}...
How do I create a right click context menu in Java Swing?
... is a bit old - as are the answers (and the tutorial as well)
The current api for setting a popupMenu in Swing is
myComponent.setComponentPopupMenu(myPopupMenu);
This way it will be shown automagically, both for mouse and keyboard triggers (the latter depends on LAF). Plus, it supports re-using ...
How can I convert an RGB image into grayscale in Python?
... do it all in matplotlib.
Background:
http://matplotlib.sourceforge.net/api/colors_api.html
http://en.wikipedia.org/wiki/HSL_and_HSV
Alternatively, you could use PIL or the builtin colorsys.rgb_to_yiq() to convert to a colorspace with a true luma value. You could also go all in and roll your o...
Checking if an Android application is running in the background
...n.activityPaused();
}
Update
ActivityLifecycleCallbacks were added in API level 14 (Android 4.0). You can use them to track whether an activity of your application is currently visible to the user. Check Cornstalks' answer below for the details.
The wrong one
I used to suggest the following so...
What is the difference between re.search and re.match?
...Well, that's goofy. Why call it match? Is it a clever maneuver to seed the API's with unintuitive names to force me to read the documentation? I still won't do it! Rebel!
– Sammaron
Sep 16 '16 at 15:14
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HTML5 record audio to file
...
Update now Chrome also supports MediaRecorder API from v47. The same thing to do would be to use it( guessing native recording method is bound to be faster than work arounds), the API is really easy to use, and you would find tons of answers as to how to upload a blob fo...
What is “lifting” in Scala?
...rovides unlift to help with construction of JSON serialisers:
import play.api.libs.json._
import play.api.libs.functional.syntax._
case class Location(lat: Double, long: Double)
implicit val locationWrites: Writes[Location] = (
(JsPath \ "lat").write[Double] and
(JsPath \ "long").write[Double...