Helper Class Spring Boot with Environment Values

Question

I would like to create a helper class, but it just failed.. The error : java.lang.NullPointerException: null

When i do this without making a static class (with autowired) it works without problem. But it's a helper class, i think the static class is the better thing.

Thanks for help

Helper.java

public final class UrlHelper {
    
    @Autowired
    private static Environment bean;
    
    public static String method(String projet) {    
        return "titi"+ bean.getProperty("property.name");
    }
}

And in my service, i use it like this :

String list = getRequest.getHTTPRequest(UrlHelper.method(projet));

Answer 1

In Spring, the @Autowired annotation allows you to resolve and inject beans into other beans. In your case, the UrlHelper class is not a bean and therefore, your Environment is not injected (stays null), hence the error. You have two options:

1. Make the UrlHelper a bean using @Component, @Service, etc. This will make your class non-static.
2. Keep the UrlHelper static, and pass the Environment as parameter. This, I believe, is the more correct approach. The Environment can be injected in the class calling the static method.