In this tutorial I am going to explain how to start Spring Cloud microservices on random ports. If you do not specify any port for each of your Spring Boot services, then they will run on the same port and only one application will start and rest of the applications will fail to start. One way to fix this problem…

Introduction The ELK Stack is made of three open-source products: 1) Elasticsearch, 2) Logstash, and 3) Kibana. Elasticsearch: It is a NoSQL database which is based on the open-source search engine called Lucene. So Elasticsearch is a search and analytics engine. Logstash: It is a data processing pipeline tool which accepts inputs from (multiple) sources, performs different transformations, and exports…

Introduction Here in this tutorial I will show you an example on how to test private methods using Junit framework. I am using Junit 5 framework to test the private method. Using Mockito framework you won’t be able to test private methods, but using PowerMock core API you will be able to test the private methods. You can also use…

Lookup Method In this tutorial I am going to show you how lookup method injection works in Spring framework. You may face a situation where you need to inject prototype scoped bean into singleton scoped bean. For singleton scoped bean a new instance or object is created and the same is returned each time it is injected or looked up….

In this tutorial I am going to discuss about what is Whitelabel Error Page and how to deal with Whitelabel Error Page in Spring Boot applications. Spring boot allows you to setup a Spring based application with minimal configurations. Spring MVC applications provide no default (fall-back) error page out of the box but Spring Boot based applications provide a fall-back…

Here I am going to build an application to show how to use Spring Cloud Bus. Let’s say you have multiple applications reading properties using Spring Cloud Config from centralized configuration files (for example, from Git repository). Spring Cloud Config is where you can have not only your all configurations centrally managed but also you can refresh them dynamically and…

Parallel Jobs In this example I am going to show you how to run multiple batch jobs parallelly in Spring Batch framework. Spring Batch is a lightweight, comprehensive batch framework designed to enable the development of robust batch applications vital for the daily operations of enterprise systems. Spring Batch provides reusable functions that are essential in processing large volumes of…

In this tutorial I am going to show you an example on deploying Spring Boot application to Heroku cloud. I will create a basic CRUD application with Spring Boot Data JPA and PostgreSQL/MySQL technologies. I will first show you how to perform CRUD operations locally, then deploy the same application in the Heroku cloud with some modifications. CRUD is an…

Here in this example I am going to show you how to allow users for OAuth2 SSO (Single Sign On) using AWS (Amazon Web Services) Cognito. I had explained how to do OAuth2 Single Sign On using Spring Boot and GitHub account. Here I am going to use AWS Cognito. You can use any other providers, such as, Google, Facebook,…

Introduction Here I am going to show you an example on how to return different data formats from REST API using Spring Boot framework. You may have a requirement that you need to return multiple formats, such as XML, JSON, etc., from the REST response, then this example may help you. This example will return XML and JSON format depending…