Volatile explained with Singleton example

"Volatile keyword in Java is used as an indicator to Java compiler and Thread that do not cache value of this variable and always read it from main memory ...
A volatile variable can be used as an alternative way of achieving synchronization in Java in some cases, like Visibility. with volatile variable, it's guaranteed that all reader thread will see updated value of the volatile variable once write operation completed, without volatile keyword different reader thread may see different values ..."

Moreo on Violate keyword & how to use it here:

Interview ...

OAuth & Spring boot

getResultStream() in JPA 2.2

"The Stream API provides a great way to process the result set. But please keep in mind that databases are highly optimized to work with huge datasets and can do that a lot faster than your Java code. So, it’s better to perform all filter, limit and sorting operations in the database and just use the Stream to iterate through the result set."

JSON Web Token (JWT)

"... a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with HMAC algorithm) or a public/private key pair using RSA"

Migrating to java9

... interesting article about issues faced by migrating from java8 to java9, and how to fix them