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WOW! How meaningful this below video explains about the name of  "I/O". Sundar Pichai talked a lot of Machine Learning Machine Learning is a very hot trend these days. Google uses it for their products. Google Assistant: Easily booking an online meal by talking with Google Assistant like a staff of partners, for example. Google Home: Hands-free calling. Google Photos: sharing suggestion, shared library, photo books and google lens. Youtube: 360 degree video, live stream. Kotlin became an official programming language for Android https://kotlinlang.org I'm on the way to Kotlin! ^^ Reference: [1]. https://www.youtube.com/watch?v=Y2VF8tmLFHw

What issues do we concern when implementing and maintaining systems? One of the most concern is debugging during maintenance: "this code crashed because it observed some unexpected value." Then, it turns out that the ideas of  no side effects  and  immutability , which functional programming promotes, can help. Shared mutable data is the root cause Shared mutable data are read and updated by more than one of the methods. Share mutable data structures make it harder to track changes in different parts of your program. An immutable object is an object that can't change its state after it's instantiated so it can't be affected by the actions of a function. It would be a dream to maintain because we wouldn't have any bad surprises about some object somewhere that unexpectedly modifies a data structure. A new thinking: Declarative programming There are two ways thinking about implementing a system by writing a program. - Imperative programming: has...

How can you design the software which is built in tiny increments? How can you ensure that the software has a good structure which is flexible, maintainable and reusable? ARE'NT YOU GOING TO MISS THE BIG PICTURE? Not really! In an agile team, the big picture evolves along with the software. How? With each iteration, the team improves the design of the system so that it is as good as it can be for the system as it is now. They focus on the current structure of the system, making it as good as it can be . How do we know if the design of software is good? Avoiding these following  symptoms of poor design (design smells) should be a way. 1. Rigidity - The design is hard to change. 2. Fragility - The design is easy to break. 3. Immobility - The design is hard to reuse. 4. Viscosity - It is hard to do the right thing. 5. Needless Complexity - Overdesign 6. Needless Repetition - Mouse abuse 7. Opacity - Disorganized expression These symptoms are similar in nature ...

I have heard of a lot of NGINX recently. One of them was it can help for security issues; for sure, it much be more. It so happens that our team has got a ton of user stories from a security audit. It's time to delve into it. What is NGINX? In order to get a basic idea and have some fun , I've just picked some available posts from my favorite Vietnamese blogger communities as below: https://kipalog.com/posts/Cau-hinh-nginx-co-ban---Phan-1 https://viblo.asia/hoang.thi.tuan.dung/posts/ZabG912QGzY6 NGINX (pronounce: Engine-X) is a web server (comparing to IIS, Apache). It can be used as a reverse proxy ( this is what I need for security issues with configuration ), load balancer and more. How to get started? I found the below path for learning NGINX by googling "learn nginx": https://www.quora.com/What-are-some-good-online-resources-to-learn-Nginx In this post, I only went first step. This is installing NGINX on macOS and taking a first look at the confi...

Getting Started It's always fun to jump right in to the "HelloWorld" app. Just go for it! Visit: https://try.github.io/levels/1/challenges/1 Cheatsheet It's time for us to store our "magic tools". Visit:  https://www.git-tower.com/blog/git-cheat-sheet Which collaboration way fit your team? Git is just a tool which doesn't teach you how to work properly in a team. It depends on your projects and you need to choose your own team workflow. Visit: https://www.atlassian.com/git/tutorials/comparing-workflows

If you heard about the term separation of concerns , you could agree this concept is very important for making a system "clean". One of the most important characteristics of a clean system is testable. Let me tell you my story about how I've just come acrosss the design pattern Proxy. Note: to get started, you can find a very simple example of the pattern Proxy  here .  Let's start! I have an interface as below: public interface DocumentGenerator { File generate(Document document) throws BusinessException; } The following is my first implementation for a concrete class of DocumentGenerator . public class DocumentGeneratorImpl implements DocumentGenerator { private Dossier dossier; private Locale locale; public DocumentGeneratorImpl(Dossier dossier, Locale locale) { validateNotNullParams(dossier, locale); this.dossier = dossier; this.locale = locale; } private void validateNotNullParams(LibertyDossier dossier, Locale locale) { if(Objec...

I n the real world, in order to use a building (hotel, supermarket, etc) we need to construct it first. This concern should be applied for software development as well. Step by step, I would like to show you the issue about no separation of constructing and using it and then I'll give you some approaches to overcome this issue. | Note : you can find the  below  demonstrated code here    Take a Look the Following Simple Application Used tools and technologies: Eclipse (Mars), JDK 1.8 I had an App which uses Controller . Controller uses Service (an interface). Finally, Service has one concrete class is DefaultService . //package vn.nvanhuong.system.separationconstructing; public class App { public static void main(String[] args) { Controller controller = new Controller(); controller.doAction(); } } public class Controller { private Service service; public void doAction(){ System.out.println("doAction in Controller"); getService().execut...