djspiewak

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

Skehmatics

#!/bin/bash

# export DBUS_SESSION_BUS_ADDRESS environment variable because cron hates me
PID=$(pgrep -u USER gnome-session-b)
export DBUS_SESSION_BUS_ADDRESS=$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$PID/environ|cut -d= -f2-)

/usr/bin/gsettings set org.gnome.shell.extensions.user-theme name 'Flat-Plat'
/usr/bin/gsettings set org.gnome.desktop.interface gtk-theme 'Flat-Plat'
/usr/bin/gsettings set org.gnome.desktop.background picture-uri 'file://WALLPAPER-PATH'
/usr/bin/gsettings --schemadir ~/.local/share/gnome-shell/extensions/drop-down-terminal@gs-extensions.zzrough.org set org.zzrough.gs-extensions.drop-down-terminal background-color 'rgb(69,90,100)'

chiquitinxx

import org.grooscript.asts.GsNative

trait JQueryRestApi {
    static String url
    static String resource

    void add(Closure onSuccess, Closure onError) {
        ajaxCall('POST', "${url}/${resource}", onSuccess, onError)
    }

akras14

Git Cheat Sheet

Commands

Getting Started

git init

or

shamil

How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

chrismccoy

# alias to edit commit messages without using rebase interactive
# example: git reword commithash message
reword = "!f() {\n  GIT_SEQUENCE_EDITOR=\"sed -i 1s/^pick/reword/\" GIT_EDITOR=\"printf \\\"%s\\n\\\" \\\"$2\\\" >\" git rebase -i \"$1^\";\n git push -f;\n}; f"

# edit all commit messages 
git rebase -i --root

# clone all your repos with gh cli tool
gh repo list --json name -q '.[].name' | xargs -n1 gh repo clone

willurd

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

silv3rm00n

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>

	<!--
		Documented at
		http://linux.die.net/man/5/fonts-conf
			
		To check font mapping run the command at terminal
		$ fc-match 'helvetica Neue'

banaslee

eXtreme Go Horse (XGH) Process

Source: http://gohorseprocess.wordpress.com


1. I think therefore it's not XGH.
In XGH you don't think, you do the first thing that comes to your mind. There's not a second option as the first one is faster.

2. There are 3 ways of solving a problem: the right way, the wrong way and the XGH way which is exactly like the wrong one but faster.
XGH is faster than any development process you know (see Axiom 14).