mvc-api | Sample Banking app based on ASP.Net MVC API | Model View Controller library

Static files don't need to be in the WEB-INF folder. We put JSP files in there to protect them from the public. The assets can go straight in the src/main/webapp folder. This is the root where the default servlet will serve the static files.

So let's say you have the following structure

I'm confused. You've configured the persistence unit to point to a data source managed by your container (java:global/mariadb) and also configured the JDBC properties? You have to make up your mind, either use the datasource provided by the container or configure it yourself, but not both at the same time (in other words, the jta-data-source property is mutually exclusive with the javax.persistence.jdbc.* properties).

You're getting the error because you've set the persistence unit to use JTA, and then you're trying to begin a transaction somewhere using em.getTransaction(), which is not allowed for JTA. Also, you put @PersistenceContext on top of entityManager, which means right after the constructor gets invoked, the entityManager is probably getting overwritten by an injected instance.

The solution is, assuming you do actually want to use JTA, to inject the EntityManager using @PersistenceContext (you shouldn't have to initialize it manually), and then annotating the methods that you want to execute atomically with @Transactional, instead of trying to use entityManager.getTransaction().