Depending on whether the transaction encloses the loop, batching typically already happens in your case. JPA will collect all your updates in its L1 cache, and typically write that all to the DB in a batch when the transaction commits. This is not really that different with batching in JDBC, where every batch-item you add … Read more
The EJB or Enterprise Java Beans are plain java classes (since version 3.0) with annotations that enable to you write the business logic of your applications and later deploy it (or install) on a Java Enterprise Edition Server. You must consider use EJB if you wish to take advantage of the following services provided by … Read more
For your use case where the application runs on one server and the database runs on another, the choice between EJB and Spring is irrelevant. Every platforms supports this, be it a Java SE application, a simple Servlet container like Tomcat or Jetty, PHP, Ruby on Rails, or whatever. You don’t need any kind of … Read more
I think the best way is to put a break point in the constructor of java.lang.TypeNotPresentException and check the second argument of type Throwable to know the root cause
Updating maven project after importing it has fixed this issue for me: Right click on the project –> Maven –> Update project.
What you do is called a projection. That’s when you return only a scalar value that belongs to one entity. You can do this with JPA. See scalar value. I think in this case, omitting the entity type altogether is possible: Query query = em.createNativeQuery( “select id from users where username = ?”); query.setParameter(1, “lt”); … Read more
Although you are getting valid results, the SQL query fetches all data and it’s not as efficient as it should. So, you have two options. Fixing the issue with two SQL queries that can fetch entities in read-write mode The easiest way to fix this issue is to execute two queries: . The first query … Read more
The terms “jta-datasource” and “resouce-local datasource” are a little vague to me. I guess you actually refer to the jta-datasource and non-jta-datasource elements. In short: if the transaction type of the persistence unit is JTA, the jta-datasource element is used to declare the JNDI name of the JTA data source that will be used to … Read more
Fixed it by removing CascadeType.MERGE on Permission entity
There won’t be much difference between EJB3 and Spring based on Performance. We chose Spring for the following reasons (not mentioned in the question): Spring drives the architecture in a direction that more readily supports unit testing. For example, inject a mock DAO object to unit test your business layer, or utilize Spring’s MockHttpRequest object … Read more