java annotations attribute value must be constant

In the above example, because we don't have any car.type property in application.properties, Spring will assign Sedan to the type variable as the default value. Default Valueĭefault values are used as a 'fallback' if the property we wish to inject isn't defined or missing: private String type Most of the time, we'd use this approach to inject configuration values from the application.properties file into beans. In this example, the values for the variables are being read from the application.properties file and assigned to them during bean creation.

We will use the default property file for Spring Boot - application.properties, where we can define variables that we can access afterwards:Ĭar.brand= Audi car.color= Red car.power= 150 private String private String private int power Injecting values from properties files with the help of annotation is probably the most used use-case in real-life applications. Spring will convert the value to the specified type and the assignment will be done without any problems - even if we are passing String values to int or boolean variables. It's very important to note that the argument passed to the annotation can only be a String. Basic Assignmentįor the easiest examples, we will assign values to three different fields using the annotation by giving them explicit values: private String private int private boolean passedAssesmentTest It is commonly used for injecting values into configuration variables - which we will show and explain in the next part of the article. The main focus of this article is to help you understand how Spring's annotation is a Java annotation that is used at the field or method/constructor parameter level and it indicates a default value for the affected argument.

Java annotations attribute value must be constant