The problem Sometimes we want to register a default Entity Listeners which are called as soon an entity is persisted, without adding the @EntityListeners annotation to our classes, as in most cases we anyway provide interfaces so we can access data on the entity itself. The problem is, that we cannot annotate our entity listener with…
Problem Sometimes it is confusing how fragments work in Android and interesting side effects like: Why have Fragments empty constructors? Why shouldn’t I pass state variables like they are? Why do I need this Fragment transactions? What does addToBackStack mean and do I need it? Why is sometimes the Activity null in my fragment? Overview…
Problem Often we want to connect to create a secure SSL connection to an HTTPs endpoint which is secured by a self-signed Certificate. If we do so just with a simple call we usually face an nice exception like: Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested…
The Problem Recently using MongoDB and Spring Data I encountered an interesting issue. Saving an Entity which was loaded by @DBRef(lazy = true) wasn’t possible together with the activated ValidatingMongoEventListener. Each time the following error occurred: javax.validation.ConstraintViolationException at org.springframework.data.mongodb.core.mapping.event.ValidatingMongoEventListener.onBeforeSave(ValidatingMongoEventListener.java:65) at org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener.onBeforeSave(AbstractMongoEventListener.java:144) at org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener.onApplicationEvent(AbstractMongoEventListener.java:90) at org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener.onApplicationEvent(AbstractMongoEventListener.java:33) at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:163) at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:136) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:381) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:335) at org.springframework.data.mongodb.core.MongoTemplate.maybeEmitEvent(MongoTemplate.java:1633) at org.springframework.data.mongodb.core.MongoTemplate.doSave(MongoTemplate.java:986) at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:933)…
Where are many articles around comparing the serialization between different frameworks and of course different encodings. I came around recently the problem that I needed a very fast serialization for pretty simple objects but between different platforms (embedded device with C, Android Java, iOS Objective-C and Java Backend). Well first reaction, let us just take…
Yaml Configuration Important to notice hibernate.dialect must be set driver-class-name must be set it needs to be the MySQL5InnoDBDialect or MySQL57InnoDBDialect instead of the MySQLInnoDBDialect Dependencies in Maven
Sometimes it is useful haven the Web Scopes in Unit Tests. Usually Spring just show this very useful error in the Unit Test: Caused by: java.lang.IllegalStateException: No Scope registered for scope ’session‘ at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:334) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194) at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1120) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1044) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:942) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:533) … 28 common frames omitted You can easily have all needed…
I had recently a very interesting problem using Spring Boot and the automagic concerning the configuration. The Problem org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‚demo.MyApplicationTests‘: Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String demo.MyApplicationTests.url; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder ‚my.url‘ in string value „${my.url}“ at…
In some projects you may encounter the so called „strong id pattern“. What is it? Strong IDs are simply wrapped primitive or simple types into classes. Just remember what we did in Java before the Enum come around. We had just Strings or Numbers in the code which we used to assign well known values…
A common case is to validate date inputs in Java e.g. to avoid the nice and friendly typos like 06/01/1500. Nevertheless by default where is not to much support to handle this very common case. So let’s fix this together: Annotation first The first we need is a JSR annotation which we use to annotate…
