title: Error during spring vault configuration in spring boot application
body: <pre><code>2016-12-28 12:26:01.001  INFO 6168 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@5b218417: startup date [Wed Dec 28 12:26:00 IST 2016]; root of context hierarchy
  2016-12-28 12:26:01.438  INFO 6168 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'configurationPropertiesRebinderAutoConfiguration' of type [class org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration$$EnhancerBySpringCGLIB$$bb2e5eda] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
  2016-12-28 12:26:02.058  WARN 6168 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'propertySourceBootstrapConfiguration': Unsatisfied dependency expressed through field 'propertySourceLocators'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'vaultPropertySourceLocator' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Unsatisfied dependency expressed through method 'vaultPropertySourceLocator' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'vaultTemplate' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Unsatisfied dependency expressed through method 'vaultTemplate' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'clientAuthentication' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.vault.authentication.ClientAuthentication]: Factory method 'clientAuthentication' threw exception; nested exception is java.lang.IllegalArgumentException: Token (spring.cloud.vault.token) must not be empty
  2016-12-28 12:26:02.070  INFO 6168 --- [           main] utoConfigurationReportLoggingInitializer : 
  
  Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
  2016-12-28 12:26:02.087 ERROR 6168 --- [           main] o.s.b.SpringApplication                  : Application startup failed
  
  org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'propertySourceBootstrapConfiguration': Unsatisfied dependency expressed through field 'propertySourceLocators'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'vaultPropertySourceLocator' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Unsatisfied dependency expressed through method 'vaultPropertySourceLocator' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'vaultTemplate' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Unsatisfied dependency expressed through method 'vaultTemplate' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'clientAuthentication' defined in org.springframework.cloud.vault.config.VaultBootstrapConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.vault.authentication.ClientAuthentication]: Factory method 'clientAuthentication' threw exception; nested exception is java.lang.IllegalArgumentException: Token (spring.cloud.vault.token) must not be empty
      at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:592) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:370) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1219) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:551) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:754) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:134) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.cloud.bootstrap.BootstrapApplicationListener.bootstrapServiceContext(BootstrapApplicationListener.java:138) [spring-cloud-context-1.1.4.BUILD-SNAPSHOT.jar:1.1.4.BUILD-SNAPSHOT]
      at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:84) [spring-cloud-context-1.1.4.BUILD-SNAPSHOT.jar:1.1.4.BUILD-SNAPSHOT]
      at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:62) [spring-cloud-context-1.1.4.BUILD-SNAPSHOT.jar:1.1.4.BUILD-SNAPSHOT]
      at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:166) [spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:138) [spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:121) [spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
      at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:68) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:337) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
      at com.oauth.AuthenticationServerApplication.main(AuthenticationServerApplication.java:42) [classes/:?]
  </code></pre>