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“Java DateFormat is not threadsafe” what does this leads to?

... threads use a shared SimpleDateFormat. Program: public static void main(String[] args) throws Exception { final DateFormat format = new SimpleDateFormat("yyyyMMdd"); Callable<Date> task = new Callable<Date>(){ public Date call() throws Exception { return ...
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Rails migrations: self.up and self.down versus change

...d only delete this column on down def up add_column :users, :location, :string User.update_all(location: 'Minsk') end def down remove_column :users, :location end But: You had to avoid using change method which allows to save some time. For example, if you didn’t need to update column v...
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Appending an element to the end of a list in Scala

...e element is appended, and the ListBuffer converted back (pretty much like String and StringBuilder in Java), but that's just a guess. – Landei Aug 9 '13 at 9:27 ...
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How do I pass a string into subprocess.Popen (using the stdin argument)?

...current Python 3 version, you could use subprocess.run, to pass input as a string to an external command and get its exit status, and its output as a string back in one call: #!/usr/bin/env python3 from subprocess import run, PIPE p = run(['grep', 'f'], stdout=PIPE, input='one\ntwo\nthree\...
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Add more than one parameter in Twig path

...ge } since they are required fields. It will make your url's prettier, and be a bit easier to manage. Your Controller would then look like public function projectAction($project, $user) share | ...
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In javascript, is an empty string always false as a boolean?

...this behavior: ToBoolean The result is false if the argument is the empty String (its length is zero); otherwise the result is true Quote taken from http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf ...
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DbEntityValidationException - How can I easily tell what caused the error?

...more details. The validation errors are: The field PhoneNumber must be a string or array type with a maximum length of '12'; The LastName field is required. You can drop the overridden SaveChanges in any class that inherits from DbContext: public partial class SomethingSomethingEntities { ...
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How to scale threads according to CPU cores?

...d run() { // do one task } }); or Future<String> future = pool.submit(new Callable<String>() { public String call() throws Exception { return null; } }); future.get(); // Will block till result available This is a lot ...
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WebView and HTML5

...avaScript, Plug-ins the WebViewClient and the WebChromeClient. url = new String("http://broken-links.com/tests/video/"); mWebView = (WebView) findViewById(R.id.webview); mWebView.setWebChromeClient(chromeClient); mWebView.setWebViewClient(wvClient); mWebView.getSettings().setJavaScriptEnabled(tru...
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Why doesn't Ruby support i++ or i--​ (increment/decrement operators)?

... @LuísSoares a.capitalize! does not reassign a, it will mutate the string that a refers to. Other references to the same string will be affected and if you do a.object_id before and after the call to capitalize, you'll get the same result (neither of which would be true if you did a = a.capi...