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Hello  (<-- two spaces)
World

Hello
World

---

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Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

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host github.com
    user git
    hostname ssh.github.com
    port 443
    proxycommand socat - PROXY:<hostname>:%h:%p,proxyport=<port>

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Configure Git to use a proxy

In Brief

You may need to configure a proxy server if you're having trouble cloning or fetching from a remote repository or getting an error like unable to access '...' Couldn't resolve host '...'.

Consider something like:

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Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

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import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.Random;

/**
 * 练习 IDEA Debugger 功能
 * <p>
 * 练习: https://moqimoqidea.github.io/2017/06/02/IDEA-Debugger/
 *

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Tabs and Windows

Function	Shortcut
New Tab	⌘ + T
Close Tab or Window	⌘ + W (same as many mac apps)
Go to Tab	⌘ + Number Key (ie: ⌘2 is 2nd tab)
Go to Split Pane by Direction	⌘ + Option + Arrow Key
Cycle iTerm Windows	⌘ + backtick (true of all mac apps and works with desktops/mission control)

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public class SomeInterceptor extends HandlerInterceptorAdapter{
    @Override
  	public boolean preHandle(final HttpServletRequest request,final HttpServletResponse response,final Object handler)
  		throws Exception
  		{
      	      /*Assume the URI is user/{userId}/post/{postId} and our interceptor is registered for this URI.
      	       * This map would then be a map of two elements,with keys 'userId' and 'postId'
      	       */
  	  	 final Map<String, String> pathVariables = (Map<String, String>) request
  	  		                                                                .getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);

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Reset mysql root password in Mac OS:

First Stop MySQL:

1. Go to: 'System Preferences' >> 'MySQL' and stop MySQL

OR,

1. sudo /usr/local/mysql/support-files/mysql.server start
2. sudo /usr/local/mysql/support-files/mysql.server stop

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VIM KEYBOARD SHORTCUTS

MOVEMENT

h        -   Move left
j        -   Move down
k        -   Move up
l        -   Move right
$        -   Move to end of line
0        -   Move to beginning of line (including whitespace)