Tech Trek: A Software Engineer's Guide to Code and Beyond

This guide walks you through the steps of registering an application to integrate with Facebook. Register a new application From  http://developer.facebook.com , click on "My Apps" at the top of the page to go to the application dashboard. The dashboard shows a list of applications that the developer has already created or you can create a new one by clicking on  Add a new App.   A dialog prompts you to name your application. Enter Display Name, Contact Email and Choose a category from drop down list and click on  Create App ID . After you click, Facebook performs a Captcha check to verify that you’re not setting up applications through an automated process. Once you’ve satisfied the verification process, your application is created. The next page you see is your application’s application page. Click on the  Settings  button and it will open you a setting page of your application. Now we can configure various det...

Prerequisite : Understanding of JWT or read here to understand what is JSON Web token. As we already know that JWT is special because it is digitally signed and we can verify the authenticity of JWT using signature. Today, we will discuss on how we can actually sign this JWT using Symmetric and Asymmetric key. Symmetric key: Symmetric key uses the same key for the signature generation as well as at the time of token verification. So, extra precaution is required during the exchange of the secret key between sender and receiver. Use symmetric key if there is one sender and one receiver, the exchanging of the key will be easy.  Eg: One web application talking to the backend services. Asymmetric key: It uses a key pair. The key pair consists of a public key and a private key. JSON data will be signed using the private key and can be verified using the public key. Use Asymmetric key if you have one sender and multiple receivers as you cannot share the same key...

You should be aware of Synchronization if you are working on an application where multiple threads are accessing the same resources or else it will show you erroneous or unforeseen results. Imagine a scenario where you are doing the multiple transactions in your bank. I believe you don’t want one thread is updating your balance and in parallel, the other thread is reading your balance otherwise you will end up in error or unexpected results. Example 1: Public class HDFCBank {             Protected long balanace =1000;             Public void deposit( int amount) {                         this.balance = this.balance + amount;             } } Assume if two threads, A and B are executing t...