To allow requests against a Spring Boot REST API from a website it is necessary to configure CORS properly. In case you don’t know your client URLs you can allow all clients by adding a mapping like the following in your Kotlin project: This allows access to all endpoints from all origins via GET, POST […]
CORS configuration for REST api accessed from browser Read More »
I found lots of samples for creating a redis testcontainer in Spring Boot tests. But none of them really worked. Below is a working base class with a sample. It is based on Spring Boot 3.1.2 and latest testcontainer version at time of writing (“org.testcontainers:testcontainers:1.18.3”). The testcontainer-redis versions were avoided on purpose because they were
Redis Testcontainer with Kotlin and Spring Boot Read More »
Using Spring Events can be very handy to decouple code. But have you ever tried creating generic events and then write a listener for them? Java or Kotlin themselves don’t prevent you from doing so but when you try receiving the events you will see that it doesn’t work. The reason for this is type
Using Generic Spring Boot Events Read More »
With Spring Boot 3 some classes were deprecated and also the Keycloak adapter and the admin client stopped working in an application I am maintaining. In https://blog.coffeebeans.at/archives/1904 I already showed how to instantiate a WebClient which is the new way Spring wants us to call external APIs – not considering external libs like feign now.
OAuth2 client with Spring Boot 3 Read More »
RestTemplate is dead and everybody should use WebClient now. That’s what you find everywhere so I had a look how to configure an instance of WebClient properly: This defines a bean genericWebClient with Spring Boot configured Jackson ObjectMapper instance. Here is also the code for the WebClientLoggerBuilder: This simply logs method, path and headers of
Spring Boot WebClient with request logging Read More »
While using Java and Kotlin with Spring Boot the following exception occurs and it’s quite hard to find how to fix it. The simple solution is to add the following top level config in your gradle file:
duplicate but no duplicate handling strategy has been set – gradle DuplicationStrategy Read More »
When upgrading to the latest tools and libraries in a Spring Boot application with OpenAPI code generator in place the OpenAPI Kotlin generator introduced jakarta.annotation:jakarta.annotation-api. But with this in place the application refused to start with something like org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat…Caused by: java.lang.IllegalStateException:
java.lang.ClassNotFoundException: javax.annotation.PostConstruct Read More »
Project lombok has become a defacto standard in close to every Java project I see. Because of this I want to also write about the ongoing log4j problems as described under https://blog.coffeebeans.at/archives/1709. The annotation @Log4j allows to create a log4j logger field in the annotated class. This of course implicates that your project is using
Lombok and log4shell Read More »
I’ve started to write a simple plugin to analyse gradle projects and send dependency information to a central server. This way I want to get insight into all projects in the company and check if there is some log4j2 dependency below 2.16.0. You can find the code under https://github.com/mbogner/gradle-status-plugin. The plugin was accepted and is
gradle status plugin Read More »
I was looking for a way to validate JSON data structure with the schema saved in the database. PostgreSQL has a very cool way to store json in JSONB fields but the question was how to validate this without extra PostgreSQL plugins and integrated in hibernate’s lifecycle with bean validation. Under https://github.com/mbogner/schema-validator I came up
JSON in PostgreSQL with application side validation Read More »