spring-boot: EL dependencies missing in spring-boot-starter

In http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-external-config-validation, it’s stated that “Spring Boot will attempt to validate external configuration, by default using JSR-303 (if it is on the classpath).”.

It’s not always the case as this code can reproduce :

• pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.0.RELEASE</version>
    </parent>
    <groupId>fr.romainmoreau.test</groupId>
    <artifactId>test</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
        </dependency>
    </dependencies>
</project>

• TestApplication.java

package fr.romainmoreau.test;

import javax.validation.constraints.Min;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties
public class TestApplication {
    public class TestProperties {
        @Min(3)
        private int value;

        public int getValue() {
            return value;
        }

        public void setValue(int value) {
            this.value = value;
        }
    }

    @Bean
    @ConfigurationProperties(prefix = "test")
    public TestProperties testProperties() {
        return new TestProperties();
    }

    public static void main(String[] args) {
        SpringApplication.run(TestApplication.class, args);
    }
}

• application.properties

test=4

When runned, this sample will produce the following stack trace :

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor': Invocation of init method failed; nested exception is javax.validation.ValidationException: Unable to instantiate Configuration.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1566)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:198)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:199)
    at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:615)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:465)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:321)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:961)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:950)
    at fr.romainmoreau.test.TestApplication.main(TestApplication.java:34)
Caused by: javax.validation.ValidationException: Unable to instantiate Configuration.
    at javax.validation.Validation$GenericBootstrapImpl.configure(Validation.java:279)
    at org.springframework.validation.beanvalidation.LocalValidatorFactoryBean.afterPropertiesSet(LocalValidatorFactoryBean.java:223)
    at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor$Jsr303ValidatorFactory.run(ConfigurationPropertiesBindingPostProcessor.java:361)
    at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.afterPropertiesSet(ConfigurationPropertiesBindingPostProcessor.java:174)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1625)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1562)
    ... 14 common frames omitted
Caused by: javax.validation.ValidationException: HV000183: Unable to load 'javax.el.ExpressionFactory'. Check that you have the EL dependencies on the classpath
    at org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.<init>(ResourceBundleMessageInterpolator.java:172)
    at org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.<init>(ResourceBundleMessageInterpolator.java:118)
    at org.hibernate.validator.internal.engine.ConfigurationImpl.<init>(ConfigurationImpl.java:110)
    at org.hibernate.validator.internal.engine.ConfigurationImpl.<init>(ConfigurationImpl.java:86)
    at org.hibernate.validator.HibernateValidator.createGenericConfiguration(HibernateValidator.java:41)
    at javax.validation.Validation$GenericBootstrapImpl.configure(Validation.java:276)
    ... 19 common frames omitted