Spring Boot: @Value returns always null

Few things for you to cross check apart from @Plog's answer.

static variables can't be injected with value. Check @Plog's answer.

• Make sure the class is annotated with @Component or @Service
• The component scan should scan the enclosing package for registering the beans. Check your XML if xml enabled configuration.
• Check if the property file's path is correct or in classpath.

The other answers are probably correct for the OP.

However, I ran into the same symptoms (@Value-annotated fields being null) but with a different underlying issue:

import com.google.api.client.util.Value;

Ensure that you are importing the correct @Value annotation class! Especially with the convenience of IDEs nowadays, this is a VERY easy mistake to make (I am using IntelliJ, and if you auto-import too quickly without reading WHAT you are auto-importing, you might waste a few hours like I did).

Of course, the correct class to import is:

import org.springframework.beans.factory.annotation.Value;

For the ones still facing the issue after all the preceding suggestions, make sure you are not accessing that variable before the bean has been constructed.

That is:

Instead of doing this:

@Component
public MyBean {
   @Value("${properties.my-var}")
   private String myVar;

   private String anotherVar = foo(myVar); // <-- myVar here is still null!!!
}

do this:

@Component
public MyBean {
   @Value("${properties.my-var}")
   private String myVar;

   private String anotherVar;

   @PostConstruct  
   public void postConstruct(){

      anotherVar = foo(myVar); // <-- using myVar after the bean construction
   }
}

Hope this will help someone avoid wasting hours.

You can't use @Value on static variables. You'll have to either mark it as non static or have a look here at a way to inject values into static variables:

https://www.mkyong.com/spring/spring-inject-a-value-into-static-variables/

EDIT: Just in case the link breaks in the future. You can do this by making a non static setter for your static variable:

@Component
public class MyComponent {

    private static String directory;

    @Value("${filesystem.directory}")
    public void setDirectory(String value) {
        this.directory = value;
    }
}

The class needs to be a Spring bean though or else it won't be instantiated and the setter will be not be accessible by Spring.