troubleshooting

How to manage JPA bidirectional relationships properly

In this troubleshooting guide, we will explore how to properly map bidirectional relationships and common mapping pitfalls that cause exceptions such as DataIntegrityViolationException, a ConstrainViolationException and a PropertyValueException. We will take an unusual approach in this guide by first building the faulty software, and then we will discuss how and why this should be fixed. […]

org.hibernate.MappingException: Could not determine type for: java.util.List – Causes & Fixes

In this post, we will explore a very common Hibernate error, namely a MappingException caused by missing annotations on the Entity getters and fields. The error Let us check the following stack trace as an example: java.lang.IllegalStateException: Failed to load ApplicationContext Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘entityManagerFactory’ defined in class path resource […]

Java NullPointerException – examples, causes and fixes

Probably one of the most common and annoying exceptions to be encountered by any Java developer is the dreaded “NullPointerException”. A null pointer exception is thrown when an “illegal” referencing of a null object is performed. A “null” object is an object which is not initialized. Let us explore some examples of how a null […]

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