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@gjambet
gjambet / Calisthenics.md
Created January 9, 2018 14:45 — forked from bobuss/Calisthenics.md
The 9 Rules of Object Calisthenics

Object Calisthenics outlines 9 basic rules to apply when performing the exercise:

  • One level of indentation per method.
  • Don't use the ELSE keyword.
  • Wrap all primitives and Strings in classes.
  • First class collections.
  • One dot per line.
  • Don't abbreviate.
  • Keep all classes less than 50 lines.
  • No classes with more than two instance variables.
@alexpchin
alexpchin / Add_Existing_Project_To_Git.md
Created June 1, 2014 20:14
Add Existing Project To Git Repo

#Adding an existing project to GitHub using the command line

Simple steps to add existing project to Github.

1. Create a new repository on GitHub.

In Terminal, change the current working directory to your local project.

##2. Initialize the local directory as a Git repository.

git init
@AlainODea
AlainODea / HelloCovariance.java
Last active November 16, 2022 12:31
Exception in thread "main" java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
public class HelloCovariance {
public static void main(String[] args) {
ConcurrentHashMap<String, String> properties = new ConcurrentHashMap<>();
Set<String> keySet = properties.keySet();
}
}
@gabrielbauman
gabrielbauman / CardType.java
Last active December 13, 2023 04:21
A Java enum representing credit card types (Visa, Mastercard etc) that can detect card type from a credit card number.
package com.gabrielbauman.gist;
import java.util.regex.Pattern;
public enum CardType {
UNKNOWN,
VISA("^4[0-9]{12}(?:[0-9]{3}){0,2}$"),
MASTERCARD("^(?:5[1-5]|2(?!2([01]|20)|7(2[1-9]|3))[2-7])\\d{14}$"),
AMERICAN_EXPRESS("^3[47][0-9]{13}$"),