Sometimes may be better to handle the rules yourself — I want to share about the difficulties I ran into when using a rule engine. The specific tool I used is Drools. I still think rule engine has its place in the decision making process, but in practice it is only useful if the rules has no dependencies on each…

A beginner guide to authentication and authorization — Like the http protocol were designed to transfer information between networked devices, SSO, OIDC, OAuth2 are all protocols designed to grant user access permission to resource between services. They are all related because they are extended concept of one another, but they solve different aspect of this user permission problem.

The most critical piece of the debug process — Use Case The backend application I work on use Splunk for the logging service. Splunk provide an easy way to view our logs once our application is deployed on Azure. Splunk has a powerful search and filter feature. It is also the root of our bug discovery and onCall process. …

What goes on in this api call? — One major feature I been working on is “Export Building”. It is an api that serves a zip csv file to the frontend when user click download. This article documents the problems I solved in this api: Response type Error handling Asynchronous processing Zip logic Java Stream OpenCSV Verify on…

Why are tables designed this way? — Introduction to database concepts Candidate keys are a minimum sets of attributes that can uniquely identify a row in a table Primary key is one of the Candidate key chosen to uniquely identify a row in the table Super key is a Candidate key + other attributes All Candidate keys are Super keys. …

https://www.udemy.com/course/microservices-with-spring-boot-and-spring-cloud/learn/lecture/8005594#overview Web Service Definition: Software designed to support interoperable machine-to-machine interaction over a network service definition should define: * request responses format * request structure * response structure * endpoint transport define how a service is called * over HTTP or MQ (queue)

You thought it is straightforward… until you try it — If you are interested in the theory: https://developer.android.com/training/testing/fundamentals This documentation is mostly a summarization from https://developer.android.com/codelabs/advanced-android-kotlin-training-testing-basics#0 https://developer.android.com/codelabs/advanced-android-kotlin-training-testing-test-doubles#0 https://developer.android.com/codelabs/advanced-android-kotlin-training-testing-survey#0

The messy stuff no one’s willing to talk about — I have to start off by saying testing is my least favorite part in Android development. If you have a use case that is a little more complex than what is shown in the documentation, you will likely run into some sort of issue. Problem: How to load test data when testing a specific page? Lets say we want to test…

Do you really need to import a library? — I assume you already understand what is geohash. This post focus on its algorithm and implementation. If you are evaluating the existing libraries versus coding it up yourself, this post is for you. For general information see: Geohashing What is geohashing exactly?medium.com Geohash Implementation Lets do an example, convert latitude and longitude (39.92324, 116.3906) into geohash.