Introduction In this example I am going to show you how to use Spring’s MultiValueMap in REST API. This MultiValueMap is similar to the Jersey’s MultivaluedMap. A MultiValueMap<K, V> or MultivaluedMap<K, V> is a map of key-values pairs. Each key can have zero or more values, where K – the type of keys maintained by this map and V – the…

Introduction The ability of hasPermission() method in Spring Boot Security applications is to determine the accessibility of a particular user for the application. The permission of an access can be read, write, etc. So, a particular user has defined set of access permission by which a user can perform certain activities in the application. The…

Problem Recently while I was working with Spring Security in recent versions of Spring Boot framework (2.6.6/2.6.7), I was getting the following error (Requested bean is currently in creation: Is there an unresolvable circular reference?):

Table of Contents Introduction Where is @PreAuthorize applicable? Prerequisites Project Setup MySQL Table Data Application Config Entity Classes Repository Interfaces Service Class REST Controller Class Security Config Spring Boot Main Class Testing Spring Security – PreAuthorize hasRole Source Code Introduction PreAuthorize hasRole Spring security will determine whether a user can invoke a method or not…

Table of Contents Introduction Prerequisites Project Setup MySQL Table Application Properties Entity Class Repository Interface Service Class REST Controller Spring Boot Main Class Testing Hazelcast Caching Java Config for Hazelcast Source Code Introduction In this tutorial I am going to show you an example on caching using hazelcast in Spring Boot REST APIs. The cache…

Introduction Here I am going to tell you how to use proxy server and timeout with Spring Boot RestTemplate API. If you are running your application behind a proxy server then you need to connect to REST API through proxy server and without proxy server connection you may face connection timeout error or other errors. Remember if…

Introduction In this tutorial I am going to show you how to build Spring Boot Angular CRUD Application. CRUD is an acronym and stands for Create, Read, Update and Delete operations performed through an application or APIs. Using Spring Boot application I will build REST APIs which will be used to perform CRUD operations on…

Introduction In this example I am going to show you how to start your spring boot application on HTTPS protocol. HTTPS is a secured protocol, whereas HTTP is unsecured protocol. So the data passed over the network using HTTPS protocol are generally encrypted data. The application which I am going to build is in the…

Introduction In this example I am going to show you Spring Security Pre-authentication hasrole with Spring Data JPA. In my another example I had shown the similar example on Spring Security Pre-Authentication with Spring JDBC Template. There are situations where you want to use Spring Security for authorization, but the user has already been reliably…

Introduction Here I am going to build a system to log online user activity in Spring Boot applications using HandlerInterceptor interface. As an application owner you may want to track your user activities, such as, which page they are accessing, from where requests were made to your application, from which pages to which pages they…

Introduction In this tutorial I am going to show you how to call Spring REST APIs concurrently using Java CompletableFuture. So basically REST service APIs will be invoked parallelly and in parallel execution the response time will be very less. I am going to show you how to call REST APIs concurrently using Java 8…

Table of Contents Introduction Prerequisites Download Large File Using WebClient Using RestTemplate Testing the APplication Source Code Introduction Here in this tutorial I am going to show you how to download large file using Spring REST API. Generally when you download a file, your file is stored into file system or you load it into…