I got it. The problem was my CriteraQuery needed to be of type String. This works: CriteriaBuilder builder = em.getCriteriaBuilder(); CriteriaQuery<String> query = builder.createQuery(String.class); Root<RuleVar> ruleVariableRoot = query.from(RuleVar.class); query.select(ruleVariableRoot.get(RuleVar_.varType)).distinct(true);
The issue can be a conflict between a java version and a javaassist version. If you’re using the java 8 on your server you should make sure to use the latest javassist version as well. This blog shows the origin of a conflict being inside the thymeleaf which pulls in an older javassist, the solution … Read more
I solved my problem placing the insertable=false, updatable=false in the @JoinColumn annotation in both classes, Person and Company.
I faced similar experience when using postgresql json function in native JPA query. select * from component where data ::json ->> ?1 = ?2 JPA will throw error that i have not set the named parameter :json. The solution: “select * from component where data \\:\\:json ->> ?1 = ?2”
I faced this problem not so long ago… I found this article: Performance Antipatterns of One To Many Association in Hibernate https://fedcsis.org/proceedings/2013/pliks/322.pdf in short: Bag semantics -> List / Collection + @OneToMany -> One Element Added: 1 delete, N inserts , One Element Removed: 1 delete, N inserts List semantics -> List + @OneToMany + … Read more
The issue is that you are not able to get a connection to MYSQL database and hence it is throwing an error saying that cannot build a session factory. Please see the error below: Caused by: java.sql.SQLException: Access denied for user ”@’localhost’ (using password: NO) which points to username not getting populated. Please recheck system … Read more
I created a project like you did. The structure looks like this The Classes are just copy pasted from yours. I changed the application.properties to this: spring.datasource.url=jdbc:mysql://localhost/testproject spring.datasource.username=root spring.datasource.password=root spring.datasource.driverClassName=com.mysql.jdbc.Driver spring.jpa.hibernate.ddl-auto=update But I think your problem is in your pom.xml: <?xml version=”1.0″ encoding=”UTF-8″?> <project xmlns=”http://maven.apache.org/POM/4.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd”> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.4.1.RELEASE</version> </parent> <artifactId>spring-boot-sample-jpa</artifactId> … Read more
Until Eclipse Dali gets a generic JPQL editor you can use Hibernate Tools. Hibernate Tools works with Dali and provides a HQL/JPQL query editor which uses Hibernate to execute the queries. An alternative would be to use the JPA Query Tool [JQT], an Interactive JPA query editor and runner. It might be closer to what … Read more
I’d like to write a method like <T> T getOrCreate(Class<T> klass, Object primaryKey) This won’t be easy. A naive approach would be to do something like this (assuming the method is running inside a transaction): public <T> T findOrCreate(Class<T> entityClass, Object primaryKey) { T entity = em.find(entityClass, primaryKey); if ( entity != null ) { … Read more
How can I find out that a unique constraint was violated? Exception are chained, you have to call getCause() recursively to get the provider specific exception (and maybe go down to the SQLException) to translate it into something your application can handle nicely for your user. The following will print the chain of exception: for … Read more