Top 17 Spring AOP (Aspect-Oriented Programming) Interview Questions Answers

If you are preparing for Java and Spring Developer interviews or Spring professional certification then a good knowledge of Aspect-oriented Programming or AOP is required. It's a boring and tough topic but important from a Spring interview and Spring certification point of view and that's where these 15+ AOP interview questions come really handy. You can use them to revise key AOP concepts before any telephonic or face-to-face interview as well as to learn and explore more about Aspect-Oriented Programming. In this article, I am going to share frequently asked AOP interview questions and also tried to answer AOP questions give on the official Spring certification exam guide.

20 Design Patterns and Software Design Interview Questions for Programmers

Design patterns and software design questions are an essential part of any programming interview, no matter whether you are going for a Java interview or a C#  interview. In fact, programming and design skills complement each other quite well, people who are good programmers are often good designers as well as they know how to break a problem in to piece of code or software design but these skills just don’t come. You need to keep designing, programming both small-scale and large-scale systems, and keep learning from mistakes. 

What is bean scope in Spring Framework? Example Tutorial

Java classes or POJO which are managed by Spring Framework are called Bean or Spring Beans and Bean scope in Spring framework or Spring MVC is scope for a bean managed by Spring IOC container. Bean scope refers to the lifecycle and visibility of a bean instance in spring container. The scope determines how long the bean instance will live and how it will be shared with the other parts of application. You may know that Spring is a framework that is based on Dependency Injection and Inversion of Control and provides bean management facilities to Java application. In Spring-managed environment bean (Java Classes) are created and wired by the Spring framework. Spring allows you to define how those beans will be created and the scope of the bean is one of those details. Scope are similar to access modifiers in Java which specifies visibility of a particular class. 

Difference between @RequestMapping and @GetMapping in Spring MVC? Example

Hello Java programmers, if you are wondering what is the difference between @RequestMapping and @GetMapping annotation in Spring MVC and when and how to use them then you have come to the right place. Earlier, I have shared the best Spring MVC courses and books, and In this tutorial, we are going to discuss about Spring MVC and spring boot web services. In there, most of the interviewers asked about the difference between @RequestMapping and @GetMapping annotations in spring applications. Before going to discuss the difference between these annotations, first, understand what is @RequestMapping?, How do we use the @RequestMapping?, What is a request? and types of them.

Spring Boot @Transactional Annotation Example - How to Manage Transactions using Spring Framework?

One of the most essential parts of Spring MVC is the @Transactional annotation, which provides support for transaction management and allows developers to concentrate on coding business logic rather than worrying about data integrity in the event of system failures. In other words, @Transactional annotation  simplifies the process of transaction management and it allows you to specify transactional behavior directly within your code, typically at the service layer. You can put @Transactional annotation both at the class level and method level. When you put the @Transacational at the class level, it applies to all the public method of the class but when you put the @Transacational annotation at the method level. It only applies to that method. 

4 Ways to take Heap dump in Tomcat and Java and 3 Tools to Analyse .hprof files

The heap dump is a great source of information on identifying memory related issues on Java application e.g. web and application servers like Tomcat, WebLogic, JBoss, WebSphere and IDEs like IntelliJIDEA and Eclipse. When you take heap dump all live objects of heap with their count and other details are written into a huge file (the .hprof file) for analysis. The name and location of heap dump file is provided by command you use to take the heap dump. There are many command line tools in JDK e.g. jmap and jcmd which can be used to take the heap dump in Java. 

Top 50 Java 8 Stream, Lambda, and Functional Programming Interview Questions

Hello guys, if you are preparing for Java interviews and looking for some Java 8 Stream, Lambda Expression, and other Java 8 features then you have come to the right place. Earlier, I have shared 140+ Core Java interview questions, 50 Java Programs from Interviews,  and 20+ Spring Boot questions and in this article, I am going to share Stream, Lambda expression, and other Java 8 feature-based questions.  Java 8 features are now not remained as good to know features. They have been increasingly adopted by many organizations and most of the new development encourage developers to write code in Java 8 style to take full advantage of massive CPU power available in modern servers like HP 380 Gen 8 servers, also known as G8. 

2 Reasons of org.springframework.beans.factory.BeanCreationException: Error creating bean with name [Solution]

The Spring framework is one of the most popular frameworks for developing Java applications. Apart from many goodies, it also provides a DI and IOC container that initializes objects and their dependencies and assembles them together. The Java classes created and maintained by Spring are called Spring bean. At the startup, when the Spring framework initializes the system by creating objects and their dependencies depending upon @Autowired annotation or spring configuration XML file, it throws "org.springframework.beans.factory.BeanCreationException: Error creating a bean with name X" error if it is not able to instantiate a particular Spring bean.

Top 21 Spring Framework and Spring Boot Testing Interview Questions Answers for 2 to 5 Years Experienced

Testing is an important part of Software development but many people don't pay attention to it only to find bugs in the later stages of development that can be easily avoided by unit testing. When it comes to Java and Spring Boot development, we are lucky to have JUnit, Mockito, JsonPath, AssertJ, and some in-built testing facilities on Spring Framework and Spring Boot for our testing needs. Since the advent of DevOps, there is an increased focus on automation testing and that's why unit testing and integration testing has become important topics on Java Interviews and it's essential for Java developers to have in-depth knowledge about how to test a Spring framework and Spring Boot based Java application.

Differences between @RequestParam and @PathVariable annotations in Spring MVC?

The Spring MVC framework, one of the most popular frameworks for developing a web application in Java world also provides several useful annotations to extract data from the incoming request and mapping the request to the controller, like @RequestMapping, @GetMapping, @RestController, @RequestParam, and @PathVariable. Even though both @RequestParam and @PathVariable are used to extract values from the HTTP request, there is a subtle difference between them, which makes them a useful question from a Spring Framework interview and spring certification point of view. We'll examine the subtle difference between @RequestParam and @PathVaraible in this article.

Top 25 Spring Security Interview Questions Answers for Java Developers

Hello guys, Spring Security is one of the most popular security frameworks in the Java world and I strongly believe that every experienced Java developer should learn it. Because of its popularity, there is always some question on Spring Security on Java interviews but there are not enough resources to prepare for that. That's why when  I shared the Spring MVC questions and spring boot interview question last year, a lot of you asked me to share similar interview questions on Spring Security, Spring Cloud, and Microservices. I listen to those requests and have been doing some research since then to write those articles. 

How Spring MVC Framework works? How HTTP Request is processed?

Hello guys, one of the frequently asked Spring MVC Interview questions is about explaining the flow of web requests i.e. how an HTTP request is processed from start to end. In other words, explaining the flow of requests in Spring MVC. Since many of my readers ask this question time and again, I thought to summarize the flow of request processing in a short article. It all starts with the client, which sends a request to a specific URL. When that request hits the web container like Tomcat it looks into web.xml and finds the Servlet or Filter which is mapped to that particular URL. It the delegate that Servlet or Filter to process the request. Since Spring MVC is built on top of Servlet, this is also the initial flow of requests in any Spring MVC based Java web application.

10 Examples of @RequestMapping Annotation in Spring MVC and REST

The @RequestMapping annotation is one of the most important annotation of Spring MVC which provides mapping of HTTP requests to controller methods, I mean Java methods on Controller class for processing. If you wonder, how Spring handles a particular request and which method from controller class is called for a particular request, answer lies on @RequestMapping annotation. This annotation maps web request to methods on controller class. You can apply @RequestMapping on class or method level of your controller. This is a powerful annotation and give you a lot of option to sophistically map a web request e.g. you can narrow down mapping by using HTTP headers, HTTP methods e.g. PUT or POST, and by using Query parameters.

How to limit Concurrent Login Sessions in a Java web application using Spring Security? Example

If you don't know, Spring security can limit the number of sessions a user can have in a Java web application. If you are developing a web application especially a secure web application in Java JEE then you must have come up with the requirement similar to many online banking portals have like only one session per user at a time or no concurrent session per user. If the user tries to open a new session then either an alert is shown or his previous session is closed. Even though you can also implement this functionality without using spring security but with Spring security, it's just a piece of cake with coffee :). 

2 Ways to setup LDAP Active Directory Authentication in Java - Spring Security Example Tutorial

The LDAP authentication is one of the most popular authentication mechanism around the world for enterprise application and Active directory (an LDAP implementation by Microsoft for Windows) is another widely used LDAP server. In many projects, we need to authenticate against active directory using LDAP by credentials provided in the login screen. Sometimes this simple task gets tricky because of various issues faced during implementation and integration and no standard way of doing LDAP authentication in a Java web application. Even though Java provides LDAP support but in this article, I will mostly talk about spring security because of it's my preferred Java framework for authentication, authorization, and security-related stuff.