Can anyone explain in a clear way the practical differences between the java.lang.annotation.RetentionPolicy constants SOURCE, CLASS, and RUNTIME? I’m also not exactly sure what the phrase “retaining annotation” means. 5 Answers 5
I know that it isn’t the most vital of issues, but I just realised that I can put the javadoc comment block before or after the annotation. What would we want to adopt as a coding standard? /** * This is a javadoc comment before the annotation */ @Component public class MyClass { @Autowired /** … Read more
In python 3.x, it is common to use return type annotation of a function, such as: def foo() -> str: return “bar” What is the correct annotation for the “void” type? I’m considering 3 options: def foo() -> None: not logical IMO, because None is not a type, def foo() -> type(None): using the best … Read more
I have created a simple unit test but IntelliJ is incorrectly highlighting it red. marking it as an error No beans? As you can see below it passes the test? So it must be Autowired? 43 Answers 43 I had this same issue when creating a Spring Boot application using their @SpringBootApplication annotation. This annotation … Read more
What are the major areas that we can use Annotations? Is the feature a replacement for XML based configuration? 14 Answers 14
I don’t understand why there is no inheritance in Java annotations, just as Java classes. I think it would be very useful. For example: I want to know if a given annotation is a validator. With inheritance, I could reflexively navigate through superclasses to know if this annotation extends a ValidatorAnnotation. Otherwise, how can I … Read more
If I have a @Transactional -annotation on a private method in a Spring bean, does the annotation have any effect? If the @Transactional annotation is on a public method, it works and open a transaction. public class Bean { public void doStuff() { doPrivateStuff(); } @Transactional private void doPrivateStuff() { } } … Bean bean … Read more
Today I wanted to create my first annotation interface following this documentation and I got this compiler error Invalid type for annotation member”: public @interface MyAnnotation { Object myParameter; ^^^^^^ } Obviously Object cannot be used as type of an annotation member. Unfortunately I could not find any information on which types can be used … Read more
Is it possible to set a default value for columns in JPA, and if, how is it done using annotations? 20 Answers 20
How do I search the whole classpath for an annotated class? I’m doing a library and I want to allow the users to annotate their classes, so when the Web application starts I need to scan the whole classpath for certain annotation. I’m thinking about something like the new functionality for Java EE 5 Web … Read more
