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
cd ~ | |
apt-get install libfontenc1 xfonts-75dpi xfonts-base xfonts-encodings xfonts-utils openssl build-essential libssl-dev libxrender-dev git-core libx11-dev libxext-dev libfontconfig1-dev libfreetype6-dev fontconfig -y | |
#https://github.com/wkhtmltopdf/wkhtmltopdf/releases | |
#replace arch | |
wget https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox_0.12.5-1.bionic_amd64.deb | |
dpkg -i wkhtmltox_0.12.5-1.bionic_amd64.deb | |
apt --fix-broken install |
It's now here, in The Programmer's Compendium. The content is the same as before, but being part of the compendium means that it's actively maintained.
- Create or find a gist that you own.
- Clone your gist (replace
<hash>
with your gist's hash):# with ssh git clone [email protected]:<hash>.git mygist # with https
git clone https://gist.github.com/.git mygist
node { | |
echo 'Results included as an inline comment exactly how they are returned as of Jenkins 2.121, with $BUILD_NUMBER = 1' | |
echo 'No quotes, pipeline command in single quotes' | |
sh 'echo $BUILD_NUMBER' // 1 | |
echo 'Double quotes are silently dropped' | |
sh 'echo "$BUILD_NUMBER"' // 1 | |
echo 'Even escaped with a single backslash they are dropped' | |
sh 'echo \"$BUILD_NUMBER\"' // 1 | |
echo 'Using two backslashes, the quotes are preserved' | |
sh 'echo \\"$BUILD_NUMBER\\"' // "1" |