Configuration properties for Java – map

I have the following structure in my Spring Boot yaml file:

countryConfiguration:
  NL:
    address:
      postcodeKeyboardType: ALPHANUMERIC
      postcodeExample: 1111 AA
      cityExample: Amsterdam
  ES:
    address:
      postcodeKeyboardType: NUMERIC
      postcodeExample: 11111
      cityExample: Madrid

I want to create a configuration property class to access these values. I have something like this :

@Configuration
@ConfigurationProperties
@Validated
public class CountryConfigurationProperties {

@NotNull
    private Map<String, Configuration> countryConfiguration;

public Map<String, Configuration> getCountryConfiguration() {
        return countryConfiguration;
    }

public void setCountryConfiguration(Map<String, Configuration> 
countryConfiguration) {
        this.countryConfiguration = countryConfiguration;
    }

public static class Configuration {
        private Object address;

public Object getAddress() {
            return address;
        }

public void setAddress(Object address) {
            this.address = address;
        }
    }

}

But it doesn’t work, I see:
bind to target org.springframework.boot.context.properties.bind.BindException: Cannot bind property under “” to io.bux.onboarding.application.config.CountryConfigurationProperties$$ EnhancerBySpringCGLIB$$1d9a5856 Failed:

Property: .countryConfiguration
Value: null
Reason: must not be null

If I remove the static inner class Configuration and then put in Object, it works….

I noticed that the address field is of type Object. I want it to be of type Address and have an inner class that represents the Address object.

In the code snippet below, I added an Address class to match the yml configuration you are using. I’ve tested this and it starts successfully and maps the properties accordingly.

@Validated
@Component
@ConfigurationProperties
public class CountryConfigurationProperties {

@NotNull
    private Map<String, Configuration> countryConfiguration;

public Map<String, Configuration> getCountryConfiguration() {
        return countryConfiguration;
    }

public void setCountryConfiguration(Map<String, Configuration> countryConfiguration) {
        this.countryConfiguration = countryConfiguration;
    }

public static class Configuration {
        private Address address;

public Address getAddress() {
            return address;
        }

public void setAddress(Address address) {
            this.address = address;
        }
    }

public static class Address {
        private String postcodeKeyboardType;
        private String postcodeExample;
        private String cityExample;

public String getPostcodeKeyboardType() {
            return postcodeKeyboardType;
        }

public void setPostcodeKeyboardType(String postcodeKeyboardType) {
            this.postcodeKeyboardType = postcodeKeyboardType;
        }

public String getPostcodeExample() {
            return postcodeExample;
        }

public void setPostcodeExample(String postcodeExample) {
            this.postcodeExample = postcodeExample;
        }

public String getCityExample() {
            return cityExample;
        }

public void setCityExample(String cityExample) {
            this.cityExample = cityExample;
        }
    }

}