@Autowired create null object inspite @configuration

Question

I have the following configuration class

@org.springframework.context.annotation.Configuration
public class TemplateConfiguration {

    @Bean
    public Configuration configuration() {
        Configuration configuration = new Configuration(new Version(2, 3, 23));
        configuration.setClassForTemplateLoading(TemplateConfiguration.class, "/templates/");
        configuration.setDefaultEncoding("UTF-8");
        configuration.setLocale(Locale.US);
        configuration.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
        return configuration;
    }
}

and I use it at the following @service

@Service
public class FreeMarkerService {

    @Autowired
    private Configuration configuration;

    private static final Logger logger = LoggerFactory.getLogger(FreeMarkerService.class);

    public String process() {
        try {
            Template template = configuration.getTemplate("someName");
            ....
        } catch (IOException | TemplateException e) {
            logger.error("Error while processing FreeMarker template: " + e);
            throw new RuntimeException(e);
        }
    }
}

but when I try to call process() like

FreeMarkerService f = new FreeMarkerService()
f.process()

I get a null exception cause the configuration Object is null

I want to create an instance using @Autowired and @Configuration annotations what am I doing wrong?

score 5 · Accepted Answer · answered Sep 11 '17 at 12:59

You should use the Spring instantiated FreeMarkerService object avoiding use of new keyword for objects like Controllers or Services as possible.

For example,

@Service
public class SampleService {

    @Autowired
    private FreeMarkerService freeMarkerService;

    public String callProcess() {
        return freeMarkerService.process();
    }
}

More details you can find in many posts like this.

score 2 · Answer 2 · answered Sep 11 '17 at 12:46

2

This is a member injection:

@Autowired
private static Configuration configuration;

Which spring does after instantiating the bean from its constructor. So at the time you are making that static method call spring has not injected the value.

answered Sep 11 '17 at 12:46

Raymond Stanley

91
10

so, what should I do? cause even after removing the static modifier , spring doesn't create the Configuration class , and configuration is still null – shahaf Sep 11 '17 at 12:54

score 1 · Answer 3 · answered Sep 11 '17 at 12:44

1

This is because you are trying to autowire a static field. This is not possible in Spring. Remove static from your Configuration property and it should work.

@Autowired
private Configuration configuration;

answered Sep 11 '17 at 12:44

Plog

9,164
5
41
66

score 1 · Answer 4 · answered Sep 11 '17 at 12:45

1

 @Autowired
 private static Configuration configuration;

Why autowired a static field? this is the reason. static member load as class definition load so it is not getting injected value and getting default value which is null.

answered Sep 11 '17 at 12:45

removed static, still null – shahaf Sep 11 '17 at 12:54
check your configuration class is getting injected correctly, and stop using new for instantiating. – Sep 11 '17 at 13:11

@Autowired create null object inspite @configuration

4 Answers4