Dip Developer | Java Backend Development

In this guide, we'll walk you through how to send dynamic and responsive HTML emails using Spring Boot and the Thymeleaf template engine . By the end, you’ll have a fully functional system that sends personalized emails right from your Java backend. 📁 GitHub Reference You can explore a complete working example on GitHub here: 👉  Html-Email-Spring-Boot by TheDipDeveloper 🚀 Project Setup: What You’ll Need Start by creating a Spring Boot project with these dependencies: Spring Web Spring Boot Starter Mail Thymeleaf Lombok Add These to pom.xml : < dependencies > < dependency > < groupId >org.springframework.boot</ groupId > < artifactId >spring-boot-starter-mail</ artifactId > </ dependency > < dependency > < groupId >org.springframework.boot</ groupId > < artifactId >spring-boot-starter-thymeleaf</ artifactId > </ dependency > < depe...

Sending emails is a common requirement in modern web applications — for things like user registration, password resets, or notifications. In this tutorial, we’ll walk through how to send emails in a Spring Boot application using SMTP , specifically with Gmail’s SMTP server , and demonstrate how to send both plain emails and emails with attachments . 📺 Video Demo If you prefer watching over reading, here’s a full demo of this tutorial in action: 📁 GitHub Repo  Want the complete working code? Clone the GitHub link provided below which contains all the source code. Source Code GitHub Link: https://github.com/TheDipDeveloper/Spring-Boot-Sending-Email 🧰 Prerequisites Java 17 or above Maven Spring Boot 3.x A Gmail account  🚀 Step 1: Add Spring Boot Mail Dependency First, add all the required dependency on pom.xml file < dependencies > < dependency > < groupId >org.springframework.boot</ groupId > < artifactId >spring...

 In Java 8,  Optional<T>  is a container object used to represent the presence or absence of a value. It's commonly used to avoid  null  checks and  NullPointerException .  Below are different ways to create an  Optional  object in Java 8: 1.  Using  Optional.of(T value) Creates an  Optional  with a non-null value. String name = "John" ; Optional< String > optional = Optional.of( name ); 🔴 Throws  NullPointerException  if  name  is null. 2.  Using  Optional.ofNullable(T value) Creates an  Optional  that may hold a null value. String name = getName(); // could return null Optional< String > optional = Optional.ofNullable( name ); ✅ Safe way to wrap possibly null values. 3.  Using  Optional.empty() Creates an explicitly empty  Optional . Optional< String > optional = Optional.empty(); ✅ Used to represent absence of a value clearly. 4.  Using...

  In Java, HashMap has specific behavior when it comes to handling null keys and values: ✅ null Key Handling in HashMap A HashMap allows one null key . Internally, the null key is treated specially and stored in the first bucket (index 0). If you insert another entry with null as the key, it will overwrite the previous one. ✅ null Values A HashMap allows multiple entries with null values . 🔍 Example: import java.util.HashMap ; public class NullKeyExample { public static void main ( String [] args ) { HashMap < String , String > map = new HashMap<>(); map .put( null , "first" ); // First null key map .put( "one" , "1" ); map .put( null , "second" ); // Overwrites the previous null key System . out .println( map .get( null )); // Outputs: second System . out .println( map ); // Outputs: {null=second, one=1} } } ⚠️ Notes: If you use other Map...