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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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Comprehensions in Python the Jedi way

Beautiful is better than ugly. Explicit is better than implicit.

-- The Zen of Python

I frequently deal with collections of things in the programs I write. Collections of droids, jedis, planets, lightsabers, starfighters, etc. When programming in Python, these collections of things are usually represented as lists, sets and dictionaries. Oftentimes, what I want to do with collections is to transform them in various ways. Comprehensions is a powerful syntax for doing just that. I use them extensively, and it's one of the things that keep me coming back to Python. Let me show you a few examples of the incredible usefulness of comprehensions.

All of the tasks presented in the examples can be accomplished with the extensive standard library available in Python. These solutions would arguably be more terse and efficient in some cases. I don't have anything against the standard library. To me there is a certain

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Fair warning: getting to the reasoning point of this process requires an extraordinary amount of hand waving. We're about to go down the rabbit hole.

Neo4j

Foreword

An unfortunate part of this set up is that you're going to need to set up two different programs:

1. Neo4j Server

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Quick uninstall JetBrains settings:

curl -sL https://gist.github.com/denji/9731967/raw/jetbrains-uninstall.sh | bash -s

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# coding=UTF-8
import nltk
from nltk.corpus import brown

# This is a fast and simple noun phrase extractor (based on NLTK)
# Feel free to use it, just keep a link back to this post
# http://thetokenizer.com/2013/05/09/efficient-way-to-extract-the-main-topics-of-a-sentence/
# Create by Shlomi Babluki
# May, 2013

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<?php

/*
Demos:
https://jsbin.com/gakudi/1/edit?output
https://jsbin.com/xunifo/edit?output

Usage:
php cssImage.php scale image output
*/

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if !database: wget + grep

The Federal Aviation Administration is posting PDFs of the Section 333 exemptions that it grants, i.e. the exemptions for operators who want to fly drones commercially before the FAA finishes its rulemaking. A journalist wanted to look for exemptions granted to operators in a given U.S. state. But the FAA doesn't appear to have an easy-to-read data file to use and doesn't otherwise list exemptions by location of operator.

However, since their exemptions page is just one giant HTML table for listing the PDFs, we can just use wget to fetch all the PDFs, run pdftotext on each file, and then [grep](https://medium.com/@rualthanzauva/grep-was-a-private-command-of-m

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:: Removes most telemetry/data collection/potentially unwanted behavior from Windows 7
:: Note : be careful to keep KB in descending order

:: Removes Windows 7-8.1 telemetry (part 1)
wusa /uninstall /kb:3080149
wusa /uninstall /kb:3075249
wusa /uninstall /kb:3068708
:: Removes the "Get Windows 10" (GWX)
wusa /uninstall /kb:3035583
:: Removes Windows 7-8.1 telemetry (part 2)

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The purpose of this document is to make recommendations on how to browse in a privacy and security conscious manner. This information is compiled from a number of sources, which are referenced throughout the document, as well as my own experiences with the described technologies.

I welcome contributions and comments on the information contained. Please see the How to Contribute section for information on contributing your own knowledge.

Table of Contents

• Motivation
• Audience
• TL;DR?
• Updates
• Technologies that Affect Security and Privacy