Difference between @AutoWired and @Qualifier in Spring Framework?

Hello guys, if you are preparing for Spring Framework or Spring Boot interviews then you should always prepare comparison questions like what is difference between @Qualifier and @AutoWired annotation in Spring? This kind of questions are good to demonstrate not only your knowledge but also how well you understand them and its also your chance to impress the interviewer. In the past, I have answered @Bean vs @Component and @Controller vs @RestController annotation and in this article, I am going to explain you the difference between @Autowired and @Qualifier in Spring Framework. 

How to Solve "Error starting Application Context" in Spring Framework?

 Hello guys, Spring Boot is a popular framework for building Java applications, providing a streamlined development experience. However, like any software, Spring Boot applications can encounter errors during startup. One common error that developers may encounter is the "Error starting ApplicationContext" error. This error typically indicates an issue with the application's configuration or dependencies but it's really hard to find what exactly is wrong and how to fix it. In the past, I have shared tips on how to fix error creating bean error and In this article, we will explore various solutions to fix this error and ensure a successful startup of your Spring Boot application.

Top18 Spring Cloud Features for Microservices Architecture in Java

Hello guys, If you are doing Java development using Spring Boot then you may already know that Spring Cloud is a popular open-source framework for implementing microservices in Java. It provides a wide range of features that simplify the development, deployment, and management of Microservices in Java. In this article, we will discuss some of the key features of the Spring Cloud framework that makes it an excellent framework for developing Microservices in Java. Microservices architecture is a modern approach to building complex applications as a collection of loosely coupled, independently deployable services. 

What is Backend for front-end pattern in Microservices? How to use it? Example Tutorial

Hello guys, as Organizations embrace Microservices architecture, the need for efficient communication and collaboration between front-end and back-end teams becomes crucial. To address this, the Backend for Front-End (BFF) pattern has emerged as a valuable approach. BFF pattern allows front-end developers to have dedicated back-end services that cater specifically to their needs, enabling them to build user interfaces more effectively.  In the past, I have shared several Microservices design patterns like  Event Sourcing, SAGA, Database Per Microservices, CQRS, API Gateway, Aggregator Design Pattern,  and also shared best practices to design Microservices and in this article, I am going to talk about the Backend for Front-End pattern entails and how to effectively utilize it in microservices architecture.

What is Circuit Breaker Design Pattern in Microservices? How to implement it?

Hello guys, Microservices design patterns are very important concepts for Java developers to learn, not just to create a robust, scalable, and high-performance Microservice architecture but also to do well on Java developer interviews. In the past, I have shared several Microservices design patterns like e Event Sourcing, SAGA, Database Per Microservices, CQRSAPI Gateway, and also shared best practices to design Microservices and in this article, I am going to talk about Circuit-Breaker Design Pattern, and how you can implement in Java using Spring Cloud Framework.  This is not just an important Microservice Pattern but also a popular Microservice question which I have also mentioned earlier in my article about 15 Microservices questions for Interviews. If you haven't read that article yet, I suggest read it, especially if you are preparing for Java and Microservice interviews. 

What is @Conditional annotation in Spring Framework? Example Tutorial

Hello guys, if you want to know what is @Conditional annotation in Spring Framework and Spring Boot, and how to use it then you have come to the right place. Earlier, I have shared best free courses to learn Spring Framework and Spring Boot, and in this article, you'll learn what they are, how to use them with practical examples. Spring 4.0 introduced the @Conditional annotation that is used for conditional checking for bean registration. This annotation offers more support than the @Profile annotation provided by the spring framework and most of the Spring Boot matching is attributed to this annotation. It allows you to setup features based upon certain conditions like presence of a class in classparth or a JAR File which is how Spring Boot Auto-configuration works.

Difference between @Controller vs @RestController in Spring Framework

Hello and welcome to the blog post. If you are preparing for Java or Spring Boot interview, you may have come across this topic. In this article, we are going to have a look at the difference between @Controller and @RestController annotation. Let's understand with the help of an example.
Spring Framework is a popular open-source application framework that provides infrastructure support for developing Java applications. One of the essential components of Spring Framework is the controller, which is used to handle HTTP requests and provide responses to clients. In Spring, there are two types of controllers: @Controller and @RestController.

Difference between @RequestParam and @PathVariable in Spring MVC

Hello guys, if you are wondering what is difference between @ReqestParam and @PathVaraible annotation in Spring MVC, most likely because it was asked to you on a Java and Spring interview or maybe you are just curious then you have come to the right place. In the past, I have talked about difference between @Component, @Service, @Reposistory and @Controller annotations and in this comprehensive article we are going to take an in-depth look at the difference between the two most frequently used annotations in Spring MVC. It provides two commonly used annotations, namely @RequestParam and @PathVariable, which play a significant role in parameter handling within web applications. 

Differences between OAuth 2.0 and JWT (JSON Web Token)

Hello guys, both OAuth 2.0 and JWT (JSON Web Tokens) are two widely used authentication and authorization protocols in modern web applications. While both serve similar purposes, there are some key differences between the two that are important to understand, which we will see in this article. This is also an important interview question and if you are preparing for Java and Microservices developer interviews, it's better to know how this two technology works and what are the key differences between then.  In short, OAuth 2.0 is primarily used for authorization, whereas JWT is primarily used for authentication. OAuth 2.0 uses access tokens, whereas JWT is a self-contained token. OAuth 2.0 has a complex authorization flow, whereas JWT has a simple flow. OAuth 2.0 provides better security as it reduces the risk of unauthorized access to protected resources, while JWT can be intercepted if not properly secured. OAuth 2.0 access tokens are short-lived and need to be refreshed periodically, whereas JWTs do not expire.

3 Ways to return different content types from Spring MVC Controller? @RequestMapping and ResponseEntity Example Tutorial

Hello guys, if you want to provide different types from a Controller in Spring MVC and wondering how to do that then you have come to the right place. In the past, I have shared the free Spring MVC courses, books, and interview questions and in this article, I am going to show you three ways to send different content types from Spring Controller. There are various content types for a controller and we are going to discuss them in this tutorial. So we are going to discuss how to interpret the data present in the request and response. JSON is one of the media formats that may be consumed/produced using this request-response architecture.

Difference between @RequestParam vs @RequestBody in Spring MVC? (with Example)

Hello everyone, in this article, we are going to look at an interesting topic from the Java Spring framework and the topic is, to find the difference between @RequestBody and @RequestParam. If you don't know this is one of the frequently asked Spring MVC interview question and also two of the most used annotation when creating backend of a Java web application in Spring Framework. Earlier, I have explained difference between @RequestBody and @ResponseBody in Spring MVC and REST APIs, and in this article, I am going to tell you the difference between @RequestBody and @RequestParam annotation in Spring Framework. It is worth noting that these two annotations are frequently used in Spring Boot REST API.

10 Examples of RestTemplate in Spring Framework

Hello guys, if you are wondering how to send GET and POST request to your API or Web Service from a Java based Spring Framework then you would be glad to know that You can use use RestTemplate class from Spring Framework. It's a fully functional HTTP client which is really really useful in this age of API. I have used RestTemplate to consume JSON from API before as well as sending different kind of request like POST, PUT, DELETE and PATCH to any REST API. For example, in this article, I shared how to send POST request using RestTemplate and how to set header on HTTP request using RestTemplate. Yes, RestTemplate also allow you to send headers like Authorization on Http Request. 

What is @Component annotation in Spring? What does it do?

Hello guys, One of the main reason many people use Spring Framework is Dependency injection and auto-wiring, which means you don't need to write code to create and inject dependency, Spring will do it for you. But does it do it and how @Component annotation helps? Well, In Spring, the @Component annotation is used to mark a class as a Spring bean that should be managed by Spring's Inversion of Control (IoC) container. When a class is annotated with @Component, Spring automatically scans for such components during application startup and creates instances of these components that can be used for dependency injection. The @Component annotation is the foundation for other stereotype annotations in Spring, such as @Service, @Repository, and @Controller, which are specializations of @Component. These annotations are used to further specify the role and purpose of a component in a Spring application.

How to fix "not a managed type exception" in JPA? [Solution]

Hello folks, JPA (Java Persistence API) is a widely used technology in Java applications for object-relational mapping (ORM) and working with databases. However, when using JPA, you may encounter the "not a managed type" exception, which is a common error that occurs when JPA fails to recognize an entity class as a managed type. This exception can occur due to various reasons, such as incorrect package or class names, missing annotations, or misconfiguration of JPA settings. Fixing this error requires identifying the root cause and taking appropriate steps to resolve it. In this article, we will explore different strategies and solutions to fix the "not a managed type" exception in JPA, helping you overcome this hurdle and successfully work with JPA in your Java applications.

Top 10 Spring Framework Annotations Java Developer Should Learn - Example Tutorial

Hello guys, if you are learning the Spring framework and want to know what are essential Spring annotations you should know then you have come to the right place. Earlier, I have shared the free Core Spring and Spring Boot courses and Spring certification resources for Java developers, and in this article, you will find some of the most common annotations in this article, which is a must for a Java developer to work with Spring. You will also learn what does annotation really does and why should you learn them. There is no doubt that the Spring framework is one of the most popular Java frameworks, and it has made the life of Java developers easy by providing some excellent features in the last 15 years. 

Top 5 Spring Cloud Annotations for Java Microservices

Hello guys, If you are developing a Java application for Cloud, then you should learn Spring Cloud, a great framework and extension of the popular Spring framework, which can help you to develop a cloud-native Java application. Spring Cloud provides several necessary services required for a cloud-based Java application and Microservices like configuration management, service discovery, circuit breakers, intelligent routing, micro-proxy, a control bus, one-time tokens, global locks, leadership election, distributed sessions, cluster state, etc.

What is ContextLoaderListener in Spring MVC? Example Tutorial

The ContextLoaderListner is one of the essential components of the Spring MVC framework, probably the most important after the DispatcherServlet itself. It is used to create the root context and responsible for loading beans, which are shared by multiple DispatcherServlet like beans related to the service layer and data access layer. In general, When you develop Spring MVC based web applications and also using Spring in the services layer, you need to provide two application-contexts. The first one is configured using ContextLoaderListener, and the other is set using DispatcherServlet. The DispatcherServlet is responsible for loading web component-specific beans like controllers, view resolvers, and handler mappings while, as I said before, ContextLoaderListener is accountable for loading middle-tier and data-tier beans which forms the back end of Spring applications.

How to enable HTTP Caching in Java Web application with Spring MVC? Cache-Control Header Example

One of the standard requirement in a secure Java web application is to disallow the back button of the browser or invalid the session if the user hit the back button of the browser. You might have seen this behavior while doing online banking or net banking, almost all the banks don't allow you to use the browser's back button. Your session gets terminated as soon as you hit the back button, and you have to log in again to do any transaction. Btw, have you ever checked some situations on your Servlet and JSP-based Java web application, like, if you pressed the back button of your browser after logging in, what happened? You will find that the browser takes you to the previous page.

What is @PropertySource Annotation in Java and Spring? PropertySource Example Spring Boot

Hello Java developers, if you are using Spring Framework or Spring Boot in your new project and wondering what is property source in Spring Framework and how to use @PropertySource annotation then you have come to the right place. Earlier, I have shared the best books and online courses to learn Spring Framework and in this article, I will teach you how to use @PropertySource annotation in Spring to read Environment variables and inject properties using @Value annotation. In the Spring application, one of the files that are needed to provide properties to the Spring environment is the @Configuration classes. 

How @Configuration, @Component, and @ComponentScan annotations works in Spring Framework? Component Scanning Example

Hello guys, if you are wondering how to does autowiring work in Spring Framework and how does Spring Framework find dependency in runtime then you have come to the right place. Earlier, I have explained How Spring MVC works and how Spring Security works, and In this tutorial, I will tell you how component scanning and auto-wiring works in Spring. You will also learn how to enable component scanning in a Spring application. When you develop a software application using spring, you need to tell the Spring framework where to look for Spring components. Using component scanning it is very much easier as this enables auto-detection of beans by spring container and smoothly.

How to send Email in Java using Spring Framework? JavaMailSenderImpl Example Tutorial

Hello guys, if you want to send emails from your Java application and looking for a Java + Spring Framework tutorial to send emails then you have come to the right place. Earlier, I have shared the free spring framework online courses, and today, I am going to share how to send Emails in the Java application using Spring Framework and JavaMailSenderImpl class which makes it really easy to send emails from Java application.  Email is one of the essential function of any enterprise Java application. Your application will need Email functionality to send reminders, bills, payments, confirmations, passwords, alerts, and several other kinds of system notifications.

How does HTTP Request is handled in Spring MVC? DispatcherServlet Example Tutorial

One of the common interview questions in Spring MVC is, how does the DispatcherServlet process a request in Spring MVC? or What is the role of DispatcherServlet in the Spring MVC framework? This is an excellent question for any Java or Spring web developer because it exposed the candidate's knowledge about Spring MVC architecture and how its main components like Model, View, and Controller.   The answers to this question show how much you know about the Spring MVC framework and its working. 

[Solved] java.lang.ClassNotFoundException: org.Springframework.Web.Context.ContextLoaderListener in Java and Spring

Problem : You are getting java.lang.ClassNotFoundException : org.Springframework.Web.
Context.ContextLoaderListener in your Spring-based Java Web application.
Cause: This error comes when you are using the Spring MVC framework in your Java Web application and configured org.springframework.web.context.ContextLoaderListener as a listener in your deployment descriptor also known as web.xml, but the JAR which contains this class is not available in the web application's CLASSPATH.

How to fix org.springframework.beans.factory.BeanCreationException: Error creating bean with name X [Java Spring]

If you are using the Spring framework in your Java application and getting this error during startup it means Spring is not able to initialize the bean X and add it into its application context, Why? There could be multiple reasons like a typo on the spring bean name. Let's take a closer look at the stack trace to find out the real reason:

BeanInstantiationException: Could not instantiate bean class [X]: No default constructor found; nested exception is java.lang.NoSuchMethodException: X.()

Here X is the class, which is declared as Spring bean. The error clearly says that the default constructor is not present in class X.

What is the use of DispatcherServlet in Spring MVC? Interview Question Example

Hello guys, In today's article we are going to discuss one interesting and the important Spring MVC concept, which is also a popular Spring Interview question. How DispatcherServlet works internally in Spring MVC or What is the role of DispatcherServlet in Spring MVC are some of the frequently asked Spring MVC Interview Questions. You might have seen them already during your previous Java web development interviews but if you have not, it's a good question to know. In this article, I'll answer these questions by explaining What is DispatcherServlet and its importance in Spring MVC. The DispatcherServlet is one of the important components of the Spring MVC web framework and acts as a Front Controller.

What is @Bean Annotation in Spring Framework? Example Tutorial

Hello Java programmers, if you are wondering what is @Bean annotation in Spring Framework, what is the purpose, and how to use it then you have come to the right place. Earlier, I have shared the best free Spring core and spring MVC courses and In this tutorial, you will learn the most frequently used Spring annotations @Bean, which are used to define different types of beans. Beans are the fundamentals of Spring framework, they represent the POJO class which is created and managed by Spring Framework. Whole Spring framework is about beans and their relationships. 

Spring HelloWorld Example in Java Annotations and Autowiring [Tutorial]

Spring framework has gone a couple of releases since I last share the Spring hello world example with XML configuration. In this article, I am going to explain to you how to create a Spring hello world example with Spring 4.2 release and by using Annotation for dependency injection and autowiring. So no more XML files to specify bean dependencies. It's a simple program that shows how you can use the Spring framework to create Services that are loosely coupled. The example will show you the basic concept of dependency injection by creating a simple Java application that greets the user.

How to use @ResponseBody and @RequestBody in Spring MVC and REST? Example Tutorial

Hello guys, if you are wondering what is @RequestBody and @ResponseBody annotation in Spring MVC and Spring Boot then you have come to the right place. Earlier, I have told you about the @RestController annotation and in this article, I am going to explain to you what is RequestBody and ResponseBody annotation, how to use them, and when to use them with simple examples. While working with REST API, we may need to bind HTTP requests and response bodies with the domain object. To bind this, we use we can use the @ResponseBody and @RequestBody annotations in Spring MVC. 

Top 5 Free & Paid Spring Certification Courses and Practice Tests

Many Java developers don't know that, similar to Oracle's Java certification, there is also a Spring certification program, which certifies yourself for your Spring framework skill. There are three Spring certifications currently available, the Spring Professional certification exam, also known as the Vmware Certified Spring Professional exam (VMware EDU-1202) which certifies on your general knowledge about Spring framework, Spring MVC skill, Spring Boot, Spring Data JPA, Testing with Spring and Spring Boot, and other advanced Spring skills. Earlier, SpringSource provides these certifications, but now they are provided by Vmware, the company behind the Spring framework.

How to Schedule Spring Professional Certification Exam (VMware EDU-1202) Online? [Guide]

Hello folks, even since Pivotal made the mandatory training optional for Spring certification, I have been writing a lot about Spring 5.0 Core Professional exam here. In the past, I have written about general preparation tips, books, coursesmock tests. So, after months of hard work and preparation, you are finally ready for the day. In order to schedule for the Spring certification exam, you first need to buy an exam voucher from Vmware's website. If you have taken their training course like the Core Spring training course, then you also receive a free voucher for 1 attempt.

How to test a Spring Boot application in Java? @SpringBootTest Example

Hello guys, if you are wondering how to test your Java + Spring Boot application then you are at the right place. Earlier, I have shared best Spring Boot Courses and Spring Boot + Microservice example and in this article, I will talk about how to test your Spring boot application, mainly about writing unit test and integration test for Java and Spring boot application. Unit testing and Integration testing are two skills which separates a normal developer from a professional Java developer and when it comes to testing Spring applications many Java developer doesn't really know how to do that. If you are new to Java and Spring development but keen to learn Unit testing both Java and Spring Boot application then you have come to the right place.

Top 7 Spring Boot Online Courses for Beginners in 2025 - Best of Lot [UPDATED]

Hello guys, if one of your goals is to learn Spring Boot in 2025, and I have started working towards it. As I have talked about my 3 point action plan to learn new technology, the first step is to attend some online courses and start building from that. If you are not sure what is Spring Boot and why should you learn Spring Boot, then let me tell you that it should be the first Java framework you should learn in 2025. The Spring Boot makes it really easy to work with the Spring framework by removing all the starting hurdles concerning setup and configuration. In one word, it makes it possible to write a Spring-based Java application and run them like core Java applications, like from the primary method.

How to solve java.lang.NoClassDefFoundError: org/springframework/beans/factory/SmartInitializingSingleton in Spring Boot [Solved]

Problem:
I was trying to run a HelloWorld program using Spring Boot when I got this error:

Exception in thread "main" java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer due to internal class not found. This can happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)
at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:52)
at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:92)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:174)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:136)

Top 6 Udemy Courses to Learn Microservices with Java and Spring Boot in 2025 - Best of Lot

Hello guys, if you want to learn about Microservices architecture and how to create Microservices with Java using Spring Boot and Spring cloud framework and looking for the best online courses then you have come to the right place. Earlier, I have shared the best free Microservices courses for Java programmers and in this article, I am going to share the best online courses to learn Microservices with Java in 2025. Popularity of Cloud Computing has given an exponential rise to Microservices architecture because they go hand in hand. 

Top 5 Free Udemy Courses to Learn Microservices for Java Developers in 2025 - Best of Lot

Hello Java programmers, if you want to learn Microservice architecture and look for free Microservice resources like free online courses, you have come to the right place. Earlier, I have shared the best Microservice courses for Java programmers to build Microservice using Java and the Spring framework, and today, I will share some free courses to learn Microservice in Java using Spring Boot and the Spring Cloud framework. If you don't know, Microservices is a modern architecture that goes along nicely with cloud computing and makes deployment, scaling, and even development easier. 

Top 10 Free Udemy Courses to become Fullstack Java Developer in 2025 - Best of Lot

Hello guys, if you want to become a full-stack Java developer and are looking for free online Java Full-stack development courses to kickstart your career, you have come to the right place. Earlier, I have shared the best Java full-stack development courses, and today, I will share 10 of the free online courses you can join to become a full-stack Java developer. The long journey of becoming a full-stack Java developer is not easy. You need to know all the details, from the front end to the backend. Not only these, but you also need to know how things function in databases and connectivity.

Top 10 Projects You can Build to Learn Spring Boot in 2025

Hello guys, I have always said that there is no better way to learn anything then actually doing it and its 100% true for Spring Boot, one of the popular Framework for Java application Development. In my 20 years of experience, I have found that the best way to learn Java and Spring Boot is building projects. When you build project, common task surface them like creating a List or sorting a List and then you research and learn. Those learning stuck and make you better developer. Building project also have many advantage like it allows you to use a lot of technologies like Git, IntelliJIDEA, Hibernate, APIs etc together to build something which you can showcase to your potential employer. 

Difference between @GetMapping @PostMapping @PutMapping @DeleteMapping @PatchMapping

In the world of web development, the Spring Framework is widely known for its versatility and ease of use. It provides several annotations that simplify the process of handling HTTP requests and mapping them to specific methods in Spring controllers. Among these annotations, @GetMapping, @PostMapping, @PutMapping, @DeleteMapping, and @PatchMapping are some of the most commonly used ones. In this article, we will explore each of these annotations in detail, highlighting their purposes, differences, and providing examples to better understand their usage.

10 Code Review Best Practices Every Senior Developer Should Know (2025 Edition)

Hello guys, if you are doing software development then you may know that as engineering teams scale, code review becomes not just a quality gate, but also an opportunity for mentorship, knowledge sharing, and upholding long-term code health. But sloppy reviews, unclear feedback, or bottlenecks can erode morale and slow down delivery. Here are 10 best practices I’ve refined over years of reviewing code at scale — each backed by experience — and how modern AI tools like CodeRabbit.ai can turbocharge your review workflow when used responsibly.

Top 20 Microservices Interview Questions with Answers for Java Developers

Hello guys,  if you are preparing for Java interviews then preparing for Microservice architecture is a good decision but there are not many places where you can find Microservice interview questions, so I thought to share some common Microservices questions from Java interviews. If you are a regular reader then you may know that I have been sharing spring interview questions regularly like I shared spring boot questions last year and this year, I have shared spring cloud questions and spring data jpa questions so far. You can use those articles to prepare well for any Java and Spring boot interviews, but I also suggest spending some time learning core spring concepts as those are very important.

How to Build Event-Driven Microservices with Spring Boot and Kafka? Example Tutorial

Event-driven microservices have gained immense popularity in modern software development due to their scalability, flexibility, and robustness. Leveraging technologies like Spring Boot and Kafka, developers can build highly responsive and loosely coupled systems. In this article, we will explore the fundamentals of event-driven microservices, using Spring Boot and Kafka, and finally, create a Java program that demonstrates the integration of these technologies using a real-world example.But, before we dive into the code. It’s very important to have a thorough understanding of the key terms. Let go through it one by one.

13 Spring Boot Actuator Interview Questions Answers for 5 Years Experienced

If you have used Spring Boot, you may know that Spring Boot is all about convenience, and the Spring Boot actuator is one of such features that provides a convenient way to interact with your app using HTTP and JMX. It's also essential from the Spring Boot interview point of view. While I did include some Spring Boot Actuator questions in my earlier post about frequently sked Spring boot interview questions, many of you asked for more questions to cover Spring Boot Actuator in depth, so I decided to write a separate article. In this article, we will see some popular Spring boot Actuator interview questions and, along the way, learn more about this helpful Spring boot Feature

Difference between Spring vs SpringBoot Framework in Java

Hello guys, if you have been doing Java development then you would have definitely come across both Spring and Spring Boot framework These two Java frameworks have taken the software development world by storm and have become the go-to tools for building all kinds of applications. But what exactly are Spring and Spring Boot, and how do they differ from one another? This is one of the common questions which many Java programmer ask, particularly those who are starting with software development or new to Java world. In the past, I have shared several Spring and Spring boot articles, courses, books, projects, and interview questions but in this article, I am going to answer what exactly is Spring and Spring Boot and what is the difference between them? This will also help you to decide  when to use Spring Framework or Spring Boot for Java application development. 

How to access configuration values from application.properties file in Spring Boot? Example Tutorial

Hello guys, if you are wondering how to access a value defined in your spring application configuration file then you are not alone, many Java developer face the same challenge. How to access a value defined in the application.properties file in Spring Boot is a common question that arises when you dealing with large software applications. In software applications, you need to have different environments for the QA, production, and local. So as a solution for this, you can use different configurations and update the files separately without affecting other environments by using property files.

How to Accept and Produce JSON as a response in Spring Boot? Example Tutorial

Hello everyone, welcome to the blog post. In this short tutorial, we are going to take an in-depth look at how to consume and produce JSON responses using a widely appreciated Java framework i.e. Spring Boot. As we all know Spring Boot is a framework designed to build a secure web application, microservice, REST API, and production-ready spring application. Modern-day application deals in a large amount of data, which they share in JSON format. A JSON is a standard plain text-based representation of structured data. It is one of the popular formats for data transmission over the internet. Due to its user-friendly syntax and lightweight, it helps in the process faster. 

How to configure multiple data sources in Spring Boot? Example Tutorial

Spring Boot is a popular framework for building Java applications that simplifies the development process. In some scenarios, you may need to work with multiple databases or data sources in your Spring Boot application. Earlier, we have seen how to change port of spring boot application and in this article will guide you through the process of configuring and using two data sources in Spring Boot. We will explore various approaches and provide practical examples to help you effectively manage multiple data sources in your application.

How to Configure CORS in a Spring Boot + Spring Security application

Cross-Origin Resource Sharing (CORS) is an essential mechanism for controlling access to web resources across different domains. When developing a Spring Boot application with Spring Security, it is crucial to configure CORS properly to allow or restrict cross-origin requests based on security requirements. In this article, we will explore how to configure CORS in a Spring Boot + Spring Security application, ensuring secure and controlled access to resources. We will provide step-by-step instructions and relevant code examples to help you implement CORS effectively.

Difference between application.properties vs Application.json vs Application.yml in Spring Boot

Hello guys, if you have worked in any Spring Boot application then you may have noticed that there are multiple ways to declare configuration for Spring Boot application. I am sure you must have noticed application.propties, application.json, and application.yml while working in proprietary or open source Spring Boot application. When I first started, it was application.propties and it was quite familiar because I have used properties file in past for specify configuration of Java application but when I first see applcation.json and application.yml I was bit confused like what they are and does they really work? In the end I found out that they are just different ways to specify configuration for any Spring Boot application. 

Difference between Spring Boot vs Spring Cloud in Java

Hello guys, if you are wondering, what is difference between Spring Boot and Spring Cloud then you re not alone. Many Java developer are not familiar with various spring boot projects like Spring Security, Spring Data JPA, Spring Batch, Spring Boot, Spring Cloud etc and this lack of knowledge prevent them from taking full advantage of Spring Framework.  In last article, I have explained difference between Spring framework and Spring Boot and in this article we are going to discuss the difference between Spring Boot and Spring Cloud. Before we dive into the difference between the two terms. Let us take a look at different terms like Spring, Spring Boot, and Spring Cloud.

How to Handle REST exception in Spring Boot Application? Example Tutorial

Hello everyone, in this article we are going to take a look at how to handle REST API exceptions in Spring Boot. It is crucial to handle errors correctly in APIs by displaying meaningful messages as it helps API clients to address problems easily. What happens if we don’t handle the errors manually? By default, the spring application throws a stack trace, which is difficult to understand. Stack traces are mainly for developers hence it is useless for API clients. That's why its very important to use proper HTTP code and error messages to convey errors and exception to client and also logging so that support team can better handle them. Ideally you should tell what went wrong and how to fix it? For example, if the error is due to duplicate data then clearly say, already existed, try with a new one. Similarly, if authentication fail then clearly say authentication failed instead of throwing some other exception. 

How to set base URL for REST in Spring Boot? Example Tutorial

Hello guys, if you are wondering how to set base URL for REST API in Spring Boot then you have come to the right place. Earlier, I have shared best REST API Courses for Java developers, REST API Books,  and a complete guide to create RESTful Web service using Spring Boot, in this article, I will show you how to set a base URL in any spring boot application? If you don't know what is a base URL in a REST application or website, let me give you a brief overview first.  A base URL is the continuous element of your REST API or website's address. For example, you'll notice that the address portion http://twitter.com displays in the address bar whenever you log on to your Twitter account or visit a Twitter profile from your computer. This is the primary or base URL.

How to Enable Disable Spring Security in Spring Boot? Example Tutorial

Hello guys, if you are wondering how to enable and disable Spring Security in a Spring Boot based Java application then you have come to the right place. In the past, I have shared best Spring security courses25 Spring Security questions, as well multiple Spring security tutorials like how to use HTTP Basic auth in Spring Security etc.  and in this article, I will share multiple ways to enable and disable Spring Security in a Spring boot application. But, before that, if you are new to Spring Security then find out what is Spring Security and how does it work?  At its core, Spring Security is simply a bunch of servlet filters that assist you with adding authentication and authorization to your web application. 

Top 5 Spring Boot 3 Features for Java Developers

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Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean

Hello and welcome to the blog post. In this post, we are about to take a look at how to fix the ‘unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean’ in the spring boot application. Let’s understand how to fix this error. But before we dig deep into this issue. Let’s first have a look at when this error appears. 


Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean

The error appears with the following stack trace.

Exception in thread “main” org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.context.ApplicationContextException: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean.

at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:140)

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:476)

at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:124)

at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:658)

at org.springframework.boot.SpringApplication.run(SpringApplication.java:355)

at org.springframework.boot.SpringApplication.run(SpringApplication.java:920)

at org.springframework.boot.SpringApplication.run(SpringApplication.java:909)

at Application.main(Application.java:17)

Caused by: org.springframework.context.ApplicationContextException: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean.

at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.getEmbeddedServletContainerFactory(EmbeddedWebApplicationContext.java:190)

at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:163)

at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137)

… 7 more 


Now, let's see some code to understand when this error comes and how to fix it:


SpringBootPracticeApplication.java


package com.practice.springboot;



import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootConfiguration;



@SpringBootConfiguration

public class SpringBootPracticeApplication {



   public static void main(String[] args) {

      SpringApplication.run(SpringBootPracticeApplication.class, args);

   }



}



pom.xml


<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

   <modelVersion>4.0.0</modelVersion>

   <parent>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-parent</artifactId>

      <version>3.0.4</version>

      <relativePath/> <!-- lookup parent from repository -->

   </parent>

   <groupId>com.practice</groupId>

   <artifactId>spring-boot</artifactId>

   <version>0.0.1-SNAPSHOT</version>

   <name>Spring Boot Practice</name>

   <description>Spring Boot Practice Project</description>

   <properties>

      <java.version>17</java.version>

   </properties>

   <dependencies>

      <dependency>

         <groupId>org.springframework.boot</groupId>

         <artifactId>spring-boot-starter-web</artifactId>

      </dependency>



	 <dependency>

       <groupId>org.springframework.boot</groupId>

         <artifactId>spring-boot-starter-test</artifactId>

         <scope>test</scope>

	</dependency>

   </dependencies>

</project>


As you can see from the above program, we have a very simple spring boot project that fails to run as intended. There are a couple of possible solutions to this program. These approaches are discussed below.


How to fix this error?

First of all you need to ensure that your main class has the @SpringBootApplication annotation.

The @SpringBootApplication annotation is comparable to the @EnableAutoConfiguration, @ComponentScan, and @Configuration annotations with their default properties, i.e., allow adding new beans to the context or importing more configuration classes.


SpringBootPracticeApplication.java -- updated

package com.practice.springboot;



import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;



@SpringBootApplication

public class SpringBootPracticeApplication {



   public static void main(String[] args) {

      SpringApplication.run(SpringBootPracticeApplication.class, args);

   }



}


If you have followed the above step or your starter file already contains @SpringBootApplication, you need to make sure your pom.xml file also includes the spring-boot-starter-web or spring-boot-starter-tomcat dependencies, as demonstrated in the example below.
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

   <modelVersion>4.0.0</modelVersion>

   <parent>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-parent</artifactId>

      <version>3.0.4</version>

      <relativePath/> <!-- lookup parent from repository -->

   </parent>

   <groupId>com.practice</groupId>

   <artifactId>spring-boot</artifactId>

   <version>0.0.1-SNAPSHOT</version>

   <name>Spring Boot Practice</name>

   <description>Spring Boot Practice Project</description>

   <properties>

      <java.version>17</java.version>

   </properties>

   <dependencies>

      <dependency>

         <groupId>org.springframework.boot</groupId>

         <artifactId>spring-boot-starter-web</artifactId>

      </dependency>



	 <dependency>

       <groupId>org.springframework.boot</groupId>

         <artifactId>spring-boot-starter-test</artifactId>

         <scope>test</scope>

	</dependency>



<!-- Add spring-boot-starter-web or spring-boot-starter-tomcat -->



<dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-tomcat</artifactId>

</dependency>



<!-- Add spring-boot-starter-web or spring-boot-starter-tomcat -->



   </dependencies>

</project>


After following the above two approaches, the error finally disappeared and the spring application start successfully as shown from the console.

 .   ____          _            __ _ _

 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )

  '  |____| .__|_| |_|_| |_\__, | / / / /

 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.0.4)


2023-03-09T09:46:05.540+05:00  INFO 40009 --- [           main] c.p.s.SpringBootPracticeApplication      : Starting SpringBootPracticeApplication using Java 19.0.1 with PID 40009 (/home/muhammad/IdeaProjects/spring-boot/target/classes started by muhammad in /home/muhammad/IdeaProjects/spring-boot)

2023-03-09T09:46:05.545+05:00  INFO 40009 --- [           main] c.p.s.SpringBootPracticeApplication      : No active profile set, falling back to 1 default profile: "default"

2023-03-09T09:46:06.501+05:00  INFO 40009 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)

2023-03-09T09:46:06.509+05:00  INFO 40009 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]

2023-03-09T09:46:06.510+05:00  INFO 40009 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.5]

2023-03-09T09:46:06.585+05:00  INFO 40009 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext

2023-03-09T09:46:06.585+05:00  INFO 40009 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 972 ms

2023-03-09T09:46:06.964+05:00  INFO 40009 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''

2023-03-09T09:46:06.972+05:00  INFO 40009 --- [           main] c.p.s.SpringBootPracticeApplication      : Started SpringBootPracticeApplication in 1.927 seconds (process running for 2.661)


Conclusion

That's all about how to fix "Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean" error in Spring Boot. . The main subject of this post is the Spring Boot problem Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean. 

We have explored two methods to address this issue. The first step is to choose the appropriate Spring annotation, and the second is to add the missing dependency to your build.gradle or pom.xml file. I hope the information in this post has helped you to correct the issue. For more such helpful articles keep following us.

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