cspinetta

Object locking implementation in the Java HotSpot VM

The most synchronization idiom in Java is using the synchronized keyword.

The JVM supports synchronization of both methods and sequences of instructions within a method using a single synchronization construct - synchronized - which is built around an internal entity known as the intrinsic lock or monitor lock (The API specification often refers to this entity simply as a "monitor"). Intrinsic locks play a role in both aspects of synchronization: enforcing exclusive access to an object's state and establishing happens-before relationships to ensure a correct visibility amoung threads.

At bytecode level, the JVM supplies the monitorenter and monitorexit instructions to support such constructs.

At runtime level, in the Java HotSpot VM, every object has a built-in monitor (the so called intrinsic lock or monitor lock) that can be acquired by any thread.

rponte

Distributed Transactions and why you should avoid them

1. Modern technologies won't support it (RabbitMQ, Kafka, etc.);
2. This is a form of using Inter-Process Communication in a synchronized way and this reduces availability;
3. All participants of the distributed transaction need to be avaiable for a distributed commit, again: reduces availability.

Implementing business transactions that span multiple services is not straightforward. Distributed transactions are best avoided because of the CAP theorem. Moreover, many modern (NoSQL) databases don’t support them. The best solution is to use the Saga Pattern.

[...]

peterjaap

image: docker:latest

stages:
  - build
  
build:
  stage: build
  only:
    - master
  image:

qoomon

Conventional Commit Messages

See how a minor change to your commit message style can make a difference.

Tip

Have a look at git-conventional-commits , a CLI util to ensure these conventions and generate verion and changelogs

Commit Message Formats

Default

nakov

const aes = require("aes-js");
const argon2 = require("argon2");
const crypto = require("crypto");
const cryptoJS = require("crypto-js");

// Encrypt using AES-256-CTR-Argon2-HMAC-SHA-256
async function aes256ctrEncrypt(plaintext, password) {
    let argon2salt = crypto.randomBytes(16); // 128-bit salt for argon2
    let argon2Settings = { type: argon2.argon2di, raw: true,
        timeCost: 8, memoryCost: 2 ** 15, parallelism: 2,

Grin941

ACID

How does a relational database work

A beginner’s guide to ACID and database transactions

A beginner’s guide to database locking and the lost update phenomena

A beginner’s guide to read and write skew phenomena

vladimir-bukhtoyarov

import java.time.Duration;
import java.util.concurrent.locks.StampedLock;
import java.util.function.Supplier;

public class CachingSupplier<T> implements Supplier<T> {

    private final Supplier<T> targetSupplier;
    private final long cachingDurationNanos;
    private final StampedLock stampedLock = new StampedLock();

rivo

package main

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"os"
	"os/exec"
	"os/signal"

eashish93

vs Questions

---

1. http://stackoverflow.com/questions/804115 (rebase vs merge).
2. https://www.atlassian.com/git/tutorials/merging-vs-rebasing (rebase vs merge)
3. https://www.atlassian.com/git/tutorials/undoing-changes/ (reset vs checkout vs revert)
4. http://stackoverflow.com/questions/2221658 (HEAD^ vs HEAD~) (See git rev-parse)
5. http://stackoverflow.com/questions/292357 (pull vs fetch)
6. http://stackoverflow.com/questions/39651 (stash vs branch)
7. http://stackoverflow.com/questions/8358035 (reset vs checkout vs revert)

DragonBe

I posted several talks about compiling PHP from source, but everyone was trying to convince me that a package manager like Homebrew was a more convenient way to install.

The purpose of Homebrew is simple: a package manager for macOS that will allow you to set up and install common packages easily and allows you to update frequently using simple commands.

I used a clean installation of macOS Sierra to ensure all steps could be recorded and tested. In most cases you already have done work on your Mac, so chances are you can skip a few steps in this tutorial.

Apache and PHP with homebrew

I’ve made this according to the installation instructions given on GetGrav.