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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

@jkullick
jkullick / build-docker-image-without-dockerfile.md
Created December 22, 2016 08:35
Build Docker Image without Dockerfile
docker build -t $IMAGE_NAME - << EOF
FROM alpine:latest
...
EXPOSE 80
EOF
@mriska
mriska / Ember best practices.md
Last active June 23, 2016 11:23
Ember best practices
@sasxa
sasxa / emitter.service.ts
Created January 2, 2016 05:27
Angular2 Communicating between sibling components
import {Injectable, EventEmitter} from 'angular2/core';
@Injectable()
export class EmitterService {
private static _emitters: { [ID: string]: EventEmitter<any> } = {};
static get(ID: string): EventEmitter<any> {
if (!this._emitters[ID])
this._emitters[ID] = new EventEmitter();
return this._emitters[ID];
@staltz
staltz / introrx.md
Last active December 1, 2025 11:31
The introduction to Reactive Programming you've been missing
@delicon
delicon / gps.conf
Created October 3, 2013 09:58
MK GPS Config for Android
NTP_SERVER=0.europe.pool.ntp.org
NTP_SERVER=1.europe.pool.ntp.org
NTP_SERVER=2.europe.pool.ntp.org
NTP_SERVER=3.europe.pool.ntp.org
NTP_SERVER=mk.pool.ntp.org
XTRA_SERVER_1=http://xtra1.gpsonextra.net/xtra.bin
XTRA_SERVER_2=http://xtra2.gpsonextra.net/xtra.bin
XTRA_SERVER_3=http://xtra3.gpsonextra.net/xtra.bin
INTERMEDIATE_POS=1
C2K_HOST=c2k.pde.com
@plentz
plentz / nginx.conf
Last active November 27, 2025 12:39
Best nginx configuration for improved security(and performance)
# to generate your dhparam.pem file, run in the terminal
openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048