1

I am getting a null pointer exception when creating a spring boot ConfigurationProperties Map. The properties class is

@Component
@ConfigurationProperties(prefix = "thing")
public class ThingProperties {

 private Map<String, ThingLayout> layouts;

 public Map<String, ThingLayout> getLayouts() {
     return layouts == null ? new HashMap<>() : layouts;
 }

 public void setLayouts(final Map<String, ThingLayout> layouts) {
     this.layouts = new HashMap(layouts);
 }
}

The ThingLayout is a simple pojo, with the correct properties as specified by the properties file:

things.layouts:
 3042:
  itemPageIndex: 1
  itemX: 1960
  itemY: 890
  itemWidth: 400
  itemHeight: 70
  itemPattern: dd MMMM yyyy
 2151:
  itemPageIndex: 0
  itemX: 2000
  itemY: 796
  itemWidth: 500
  itemHeight: 70
  itemPattern: dd/MM/yyyy

The intent is that the properties will be bound, and I will be able to do things like

thingProperties.getLayouts().get(3042).getItemX();

The exception that I get is

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'thingProperties': Could not bind properties to ThingProperties (prefix=things, ignoreInvalidFields=false, ignoreUnknownFields=true, ignoreNestedProperties=false); nested exception is java.lang.IllegalArgumentException: Target object must not be null
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:339) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:289) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1192) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1116) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
... 47 common frames omitted
Caused by: java.lang.IllegalArgumentException: Target object must not be null
at org.springframework.util.Assert.notNull(Assert.java:115) ~[spring-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.setWrappedInstance(AbstractNestablePropertyAccessor.java:205) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.BeanWrapperImpl.setWrappedInstance(BeanWrapperImpl.java:138) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.<init>(AbstractNestablePropertyAccessor.java:165) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.BeanWrapperImpl.<init>(BeanWrapperImpl.java:131) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.BeanWrapperImpl.newNestedPropertyAccessor(BeanWrapperImpl.java:223) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.BeanWrapperImpl.newNestedPropertyAccessor(BeanWrapperImpl.java:63) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.getNestedPropertyAccessor(AbstractNestablePropertyAccessor.java:853) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyAccessorForPropertyPath(AbstractNestablePropertyAccessor.java:813) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyHandler(AbstractNestablePropertyAccessor.java:724) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyType(AbstractNestablePropertyAccessor.java:485) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.resolvePropertyName(RelaxedDataBinder.java:421) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.getActualPropertyName(RelaxedDataBinder.java:385) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.initializePath(RelaxedDataBinder.java:273) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.initializePath(RelaxedDataBinder.java:308) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.initializePath(RelaxedDataBinder.java:308) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.normalizePath(RelaxedDataBinder.java:259) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.modifyProperty(RelaxedDataBinder.java:240) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.modifyProperties(RelaxedDataBinder.java:155) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.RelaxedDataBinder.doBind(RelaxedDataBinder.java:128) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.validation.DataBinder.bind(DataBinder.java:715) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget(PropertiesConfigurationFactory.java:269) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget(PropertiesConfigurationFactory.java:241) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:334) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
... 61 common frames omitted
Improve this question

1 Answer 1

Reset to default
3

After a lot of debugging, the solution ended up being quite simple. If I change my properties class to the following it works.

@Component
@ConfigurationProperties(prefix = "thing")
public class ThingProperties {

 private Map<String, ThingLayout> layouts = new HashMap<>();

 public Map<String, ThingLayout> getLayouts() {
     return layouts;
 }

 public void setLayouts(final Map<String, ThingLayout> layouts) {
     this.layouts = new HashMap(layouts);
 }
}

Note that I am now initialising the layouts object outside of the getter.

Spring tried to create a default value for each map key in

org.springframework.beans.AbstractNestablePropertyAccessor#setDefaultValue(org.springframework.beans.AbstractNestablePropertyAccessor.PropertyTokenHolder)

The default value creation worked just fine, but the value was not set into the map properly in 

org.springframework.beans.AbstractNestablePropertyAccessor#setPropertyValue(org.springframework.beans.AbstractNestablePropertyAccessor.PropertyTokenHolder, org.springframework.beans.PropertyValue)
Improve this answer
Sign up to request clarification or add additional context in comments.

1 Comment

Note I raised a bug report with spring boot here github.com/spring-projects/spring-boot/issues/5824. It was closed as a duplicate of an issue marked as invalid, with a suggestion that the current behaviour is by design.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.